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                                                                    EXHIBIT 10.1

                          REGISTRATION RIGHTS AGREEMENT

         THIS REGISTRATION RIGHTS AGREEMENT, dated as of January 21, 2000 (this
"AGREEMENT"), between Popmail.com, a Minnesota corporation, with principal
executive offices located at 4801 West 81st Street, Suite 112, Bloomington,
Minnesota 55437 (the "COMPANY"), and the stockholders of IZ.com Incorporated, a
Delaware corporation ("IZ.COM").

         WHEREAS, upon the terms and subject to the conditions of the Agreement
and Plan of Reorganization dated as of January 21, 2000, between IZ.com and the
Company (the "REORGANIZATION AGREEMENT"), IZ.com is to be merged with and into a
wholly-owned subsidiary of the Company (the "MERGER"), all outstanding shares of
capital stock of IZ.com are to be converted into shares of Series F Preferred
Stock of the Company (the "PREFERRED SHARES") and all options, warrants and
other rights to purchase shares of capital stock of IZ.com will be converted
into equivalent options, warrants or other rights to purchase Preferred Shares;
and

         WHEREAS, to induce IZ.com to execute and deliver the Reorganization
Agreement, the Company has agreed to provide with respect to the Common Stock
issuable upon conversion of the Preferred Shares and exercise of the options and
warrants assumed by the Company certain registration rights under the Securities
Act;

         NOW, THEREFORE, in consideration of the premises and the mutual
covenants contained herein, the parties hereto, intending to be legally bound,
hereby agree as follows:

         1.   DEFINITIONS

               (a) As used in this Agreement, the following terms shall have the
meanings:

                    (i) "AFFILIATE," of any specified Person means any other
Person who directly, or indirectly through one or more intermediaries, is in
control of, is controlled by, or is under common control with, such specified
Person. For purposes of this definition, control of a Person means the power,
directly or indirectly, to direct or cause the direction of the management and
policies of such Person whether by contract, securities, ownership or otherwise;
and the terms "CONTROLLING" and "CONTROLLED" have the respective meanings
correlative to the foregoing.

                    (ii) "CLOSING DATE" means the date and time of closing of
the Merger.

                    (iii) "COMMISSION" means the Securities and Exchange
Commission.

                    (iv) "CURRENT MARKET PRICE" on any date of determination
means the closing bid price of a share of the Common Stock on such day as
reported on the Nasdaq SmallCap Market ("NASDAQ"); provided, if such security
bid is not listed or admitted to trading on the Nasdaq, as reported on the
principal national security exchange or quotation system on which such security
is quoted or listed or admitted to trading, or, if not quoted or listed or
admitted to

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trading on any national securities exchange or quotation system, the closing bid
price of such security on the over-the-counter market on the day in question as
reported by Bloomberg LP, or a similar generally accepted reporting service, as
the case may be.

                    (v) "EXCHANGE ACT" means the Securities Exchange Act of
1934, as amended, and the rules and regulations of the Commission thereunder, or
any similar successor statute.

                    (vi) "PERSON" means any individual, partnership,
corporation, limited liability company, joint stock company, association, trust,
unincorporated organization, or a government or agency or political subdivision
thereof.

                    (vii) "PROSPECTUS" means the prospectus (including, without
limitation, any preliminary prospectus and any final prospectus filed pursuant
to Rule 424(b) under the Securities Act, including any prospectus that discloses
information previously omitted from a prospectus filed as part of an effective
registration statement in reliance on Rule 430A under the Securities Act)
included in the Registration Statement, as amended or supplemented by any
prospectus supplement with respect to the terms of the offering of any portion
of the Registrable Securities covered by the Registration Statement and by all
other amendments and supplements to such prospectus, including all material
incorporated by reference in such prospectus and all documents filed after the
date of such prospectus by the Company under the Exchange Act and incorporated
by reference therein.

                    (viii) "PUBLIC OFFERING" means an offer registered with the
Commission and the appropriate state securities commissions by the Company of
its Common Stock and made pursuant to the Securities Act.

                    (ix) "REGISTRABLE SECURITIES" means the Common Stock issued
or issuable (i) upon conversion of the Preferred Shares and (ii) upon exercise
of options and warrants assumed by the Company pursuant to the Reorganization
Agreement, other than shares registered pursuant to a registration statement on
Form S-8 filed by the Company immediately after the Closing Date; provided,
however, a share of Common Stock shall cease to be a Registrable Security for
purposes of this Agreement when it no longer is a Restricted Security.

                    (x) "REGISTRATION STATEMENT" means a registration statement
of the Company filed on an appropriate form under the Securities Act providing
for the registration of, and the sale on a continuous or delayed basis by the
holders of, all of the Registrable Securities pursuant to Rule 415 under the
Securities Act, including the Prospectus contained therein and forming a part
thereof, any amendments to such registration statement and supplements to such
Prospectus, and all exhibits and other material incorporated by reference in
such registration statement and Prospectus.

                    (xi) "RESTRICTED SECURITY" means any share of Common Stock
issued or issuable upon conversion of the Preferred Shares except any such share
that (i) has been registered pursuant to an effective registration statement
under the Securities Act and sold in a manner contemplated by the prospectus
included in such registration statement, (ii) has been

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transferred in compliance with the resale provisions of Rule 144 under the
Securities Act (or any successor provision thereto) or is transferable pursuant
to paragraph (k) of Rule 144 under the Securities Act (or any successor
provision thereto), or (iii) otherwise has been transferred and a new share of
Common Stock not subject to transfer restrictions under the Securities Act has
been delivered by or on behalf of the Company.

                    (xii) "SECURITIES ACT" means the Securities Act of 1933, as
amended, and the rules and regulations of the Commission thereunder, or any
similar successor statute.

                    (xiii) "STOCKHOLDERS" means the Shareholders who are
signatories to this Agreement and any transferee or assignee of Registrable
Securities who agrees to become bound by all of the terms and provisions of this
Agreement in accordance with Section 8 hereof.

               (b) All capitalized terms used and not defined herein have the
respective meaning assigned to them in the Reorganization Agreement.

             2. REGISTRATION

               (a) FILING AND EFFECTIVENESS OF REGISTRATION STATEMENT. The
Company shall prepare and file with the Commission not later than 30 days after
receipt of a request therefore executed by a majority-in-interest of the
Stockholders (the "STOCKHOLDER NOTICE"), a Registration Statement relating to
the offer and resale of the Registrable Securities by the holders thereof and
shall use its best efforts to cause the Commission to declare such Registration
Statement effective under the Securities Act as promptly as practicable but not
later than 150 days after the date of the Stockholder Notice. The Company shall
notify the Stockholders by written notice that such Registration Statement has
been declared effective by the Commission within 24 hours of such declaration by
the Commission.

               (b) REGISTRATION DEFAULT. If the Registration Statement covering
the Registrable Securities required to be filed by the Company pursuant to
Section 2(a) hereof is not (i) filed with the Commission within 30 days after
the date of the Stockholder Notice or (ii) declared effective by the Commission
within 150 days after the date of the Stockholder Notice (either of which,
without duplication, an "INITIAL DATE"), then the Company shall make the
payments to the Stockholders as provided in the next sentence as liquidated
damages and not as a penalty. The amount to be paid by the Company to the
Stockholders shall be determined as of each Computation Date (as defined below),
and such amount shall be equal to 1% (the "LIQUIDATED DAMAGE RATE") of the
Current Market Price of the Registrable Securities held by each such Shareholder
from the Initial Date to the first Computation Date and for each Computation
Date thereafter, calculated on a pro rata basis to the date on which the
Registration Statement is filed with (in the event of an Initial Date pursuant
to clause (i) above) or declared effective by (in the event of an Initial Date
pursuant to clause (ii) above) the Commission (the "PERIODIC AMOUNT"). The full
Periodic Amount shall be paid by the Company to the each Stockholder by wire
transfer of immediately available funds within three days after each Computation
Date.

                As used in this Section 2(b), "COMPUTATION DATE" means the
date which is 30 days after the Initial Date and, if the Registration Statement
required to be filed by the Company

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pursuant to Section 2(a) has not theretofore been declared effective by the
Commission, each date which is 30 days after the previous Computation Date until
such Registration Statement is so declared effective.

               Notwithstanding the above, if the Registration Statement covering
the Registrable Securities or the Additional Registrable Securities required to
be filed by the Company pursuant to Section 2(a) hereof, is not filed with the
Commission by the 30th day after the date of the Stockholder Notice, the Company
shall be in default of this Registration Rights Agreement.

               (c) ELIGIBILITY FOR USE OF FORM S-3. The Company agrees that it
shall continue to file all reports and information required to be filed by it
with the Commission in a timely manner and take all such other action so as to
maintain eligibility for the use of Form S-3 under the Securities Act.

               (d) (i) If the Company proposes to register any of its warrants,
Common Stock or any other shares of common stock of the Company under the
Securities Act in connection with an underwritten public offering, whether or
not for sale for its own account, it will each such time, give prompt written
notice at least 20 days prior to the anticipated filing date of the registration
statement relating to such registration to each Stockholder, which notice shall
set forth such Stockholder's rights under this Section 2(d) and shall offer the
Stockholder the opportunity to include in such registration statement such
number of Registrable Securities as the Stockholder may request. Upon the
written request of a Stockholder made within 10 days after the receipt of notice
from the Company (which request shall specify the number of Registrable
Securities intended to be disposed of by such Stockholder), the Company will use
its best efforts to effect the registration under the Securities Act of all
Registrable Securities that the Company has been so requested to register by the
Stockholder, to the extent requisite to permit the disposition of the
Registrable Securities so to be registered; provided, however, that (A) the
Stockholder must sell their Registrable Securities to the underwriters selected
as provided in Section 3(b) hereof on the same terms and conditions as apply to
the Company and (B) if, at any time after giving written notice of its intention
to register any Registrable Securities pursuant to this Section 3 and prior to
the effective date of the registration statement filed in connection with such
registration, the Company shall determine for any reason not to register such
Registrable Securities, the Company shall give written notice to the Stockholder
and, thereupon, shall be relieved of its obligation to register any Registrable
Securities in connection with such registration. The Company's obligations under
this Section 2(d) shall terminate on the date that the registration statement to
be filed in accordance with Section 2(a) is declared effective by the Commission
provided that such registration statement remains current.

                    (ii) If in connection with a registration pursuant to this
Section 2(d), the managing underwriter thereof advises the Company that, in its
view, the number of shares of Common Stock, Warrants or other shares of Common
Stock that the Company and the Stockholders and any other holders of similar
registration rights intend to include in such registration exceeds the largest
number of shares of Common Stock or Warrants (including any other shares of
Common Stock or Warrants of the Company) that can be sold without having an
adverse effect on such Public Offering (the "MAXIMUM OFFERING SIZE"), the
Company will include in such registration, only that number of shares of Common
Stock or Warrants, as applicable, such that the number of shares of Registrable
Securities registered does not exceed the Maximum Offering Size, with the
difference

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between the number of shares in the Maximum Offering Size and the number of
shares to be issued by the Company to be allocated (after including all shares
to be issued and sold by the Company) among the Stockholders and any other
holders of similar registration rights pro rata on the basis of the relative
number of shares of Common Stock or Warrants offered for sale under such
registration by each of the Company and the Stockholders and any other holders
of similar registration rights.

         If as a result of the proration provisions of this Section 2(d)(ii),
any Stockholder is not entitled to include all such Registrable Securities in
such registration, such Stockholder may elect to withdraw its request to include
any Registrable Securities in such registration. With respect to registrations
pursuant to this Section 2(d), the number of securities required to satisfy any
underwriters' over-allotment option shall be allocated pro rata among the
Company and the Stockholders and any other holders of similar registration
rights on the basis of the relative number of shares of Common Stock or Warrants
otherwise to be included by each of them in the registration with respect to
which such over-allotment option relates.

         3. OBLIGATIONS OF THE COMPANY

         In connection with the registration of the Registrable Securities, the
Company shall:

               (a) Promptly (i) prepare and file with the Commission such
amendments (including post-effective amendments) to the Registration Statement
and supplements to the Prospectus as may be necessary to keep the Registration
Statement continuously effective and in compliance with the provisions of the
Securities Act applicable thereto so as to permit the Prospectus forming part
thereof to be current and useable by Stockholders for resales of the Registrable
Securities for a period of two years from the date on which the Registration
Statement is first declared effective by the Commission (the "EFFECTIVE TIME")
or such shorter period that will terminate when all the Registrable Securities
covered by the Registration Statement have been sold pursuant thereto in
accordance with the plan of distribution provided in the Prospectus, transferred
pursuant to Rule 144 under the Securities Act or otherwise transferred in a
manner that results in the delivery of new securities not subject to transfer
restrictions under the Securities Act (the "REGISTRATION PERIOD") and (ii) take
all lawful action such that each of (A) the Registration Statement and any
amendment thereto does not, when it becomes effective, contain an untrue
statement of a material fact or omit to state a material fact required to be
stated therein or necessary to make the statements therein, not misleading and
(B) the Prospectus forming part of the Registration Statement, and any amendment
or supplement thereto, does not at any time during the Registration Period
include an untrue statement of a material fact or omit to state a material fact
required to be stated therein or necessary to make the statements therein, in
light of the circumstances under which they were made, not misleading.
Notwithstanding the foregoing provisions of this Section 3(a), the Company may,
during the Registration Period, suspend the use of the Prospectus for a period
not to exceed 60 days (whether or not consecutive) in any 12-month period if the
Board of Directors of the Company determines in good faith that because of valid
business reasons, including pending mergers or other business combination
transactions, the planned acquisition or divestiture of assets, pending material
corporate developments and similar events, it is in the best interests of the
Company to suspend such use, and prior to or contemporaneously with suspending
such use the Company provides the Stockholders with written notice of such
suspension, which notice need not specify the nature of the event giving rise to
such suspension. At the end of

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any such suspension period, the Company shall provide the Stockholders with
written notice of the termination of such suspension;

     (b) During the Registration Period, comply with the provisions of the
Securities Act with respect to the Registrable Securities of the Company covered
by the Registration Statement until such time as all of such Registrable
Securities have been disposed of in accordance with the intended methods of
disposition by the Stockholders as set forth in the Prospectus forming part of
the Registration Statement;

     (c) (i) Prior to the filing with the Commission of any Registration
Statement (including any amendments thereto) and the distribution or delivery of
any Prospectus (including any supplements thereto), provide (A) draft copies
thereof to a representative designated by the Stockholders and reflect in such
documents all such comments as such representative (and its counsel) reasonably
may propose and (B) to the Stockholder representative a copy of the accountant's
consent letter to be included in the filing and (ii) furnish to each Stockholder
whose Registrable Securities are included in the Registration Statement and its
legal counsel identified to the Company, (A) promptly after the same is prepared
and publicly distributed, filed with the Commission, or received by the Company,
one copy of the Registration Statement, each Prospectus, and each amendment or
supplement thereto, and (B) such number of copies of the Prospectus and all
amendments and supplements thereto and such other documents, as such Stockholder
may reasonably request in order to facilitate the disposition of the Registrable
Securities owned by such Stockholder;

     (d) (i) Register or qualify the Registrable Securities covered by the
Registration Statement under such securities or "blue sky" laws of such
jurisdictions as the Stockholders who hold a majority-in-interest of the
Registrable Securities being offered reasonably request, (ii) prepare and file
in such jurisdictions such amendments (including post-effective amendments) and
supplements to such registrations and qualifications as may be necessary to
maintain the effectiveness thereof at all times during the Registration Period,
(iii) take all such other lawful actions as may be necessary to maintain such
registrations and qualifications in effect at all times during the Registration
Period, and (iv) take all such other lawful actions reasonably necessary or
advisable to qualify the Registrable Securities for sale in such jurisdictions;
provided, however, that the Company shall not be required in connection
therewith or as a condition thereto to (A) qualify to do business in any
jurisdiction where it would not otherwise be required to qualify but for this
Section 3(d), (B) subject itself to general taxation in any such jurisdiction or
(C) file a general consent to service of process in any such jurisdiction;

     (e) As promptly as practicable after becoming aware of such event, notify
each Stockholder of the occurrence of any event, as a result of which the
Prospectus included in the Registration Statement, as then in effect, includes
an untrue statement of a material fact or omits to state a material fact
required to be stated therein or necessary to make the statements therein, in
light of the circumstances under which they were made, not misleading, and
promptly prepare an amendment to the Registration Statement and supplement to
the Prospectus to correct such untrue statement or omission, and deliver a
number of copies of such supplement and amendment to each Stockholder as such
Stockholder may reasonably request;

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     (f) As promptly as practicable after becoming aware of such event, notify
each Stockholder who holds Registrable Securities being sold (or, in the event
of an underwritten offering, the managing underwriters) of the issuance by the
Commission of any stop order or other suspension of the effectiveness of the
Registration Statement at the earliest possible time and take all lawful action
to effect the withdrawal, recession or removal of such stop order or other
suspension;

     (g) Cause all the Registrable Securities covered by the Registration
Statement to be listed on the principal national securities exchange, and
included in an inter-dealer quotation system of a registered national securities
association, on or in which securities of the same class or series issued by the
Company are then listed or included;

     (h) Maintain a transfer agent and registrar, which may be a single entity,
for the Registrable Securities not later than the effective date of the
Registration Statement;

     (i) Cooperate with the Stockholders who hold Registrable Securities being
offered to facilitate the timely preparation and delivery of certificates for
the Registrable Securities to be offered pursuant to the registration statement
and enable such certificates for the Registrable Securities to be in such
denominations or amounts, as the case may be, as the Stockholders reasonably may
request and registered in such names as the Stockholder may request; and, within
three business days after a registration statement which includes Registrable
Securities is declared effective by the Commission, deliver and cause legal
counsel selected by the Company to deliver to the transfer agent for the
Registrable Securities (with copies to the Stockholders whose Registrable
Securities are included in such registration statement) an appropriate
instruction and, to the extent necessary, an opinion of such counsel;

     (j) Take all such other lawful actions reasonably necessary to expedite and
facilitate the disposition by the Stockholders of their Registrable Securities
in accordance with the intended methods therefor provided in the Prospectus
which are customary under the circumstances;

     (k) Make generally available to its security holders as soon as
practicable, but in any event not later than three (3) months after (i) the
effective date (as defined in Rule 158(c) under the Securities Act) of the
Registration Statement, and (ii) the effective date of each post-effective
amendment to the Registration Statement, as the case may be, an earnings
statement of the Company and its subsidiaries complying with Section 11(a) of
the Securities Act and the rules and regulations of the Commission thereunder
(including, at the option of the Company, Rule 158);

     (l) In the event of an underwritten offering, promptly include or
incorporate in a Prospectus supplement or post-effective amendment to the
Registration Statement such information as the managers reasonably agree should
be included therein and to which the Company does not reasonably object and make
all required filings of such Prospectus supplement or post-effective amendment
as soon as practicable after it is notified of the matters to be included or
incorporated in such Prospectus supplement or post-effective amendment;

     (m) (i) Make reasonably available for inspection by Stockholders, any
underwriter participating in any disposition pursuant to the Registration
Statement, and any attorney, accountant or other agent retained by such
Stockholders or any such underwriter all relevant financial and other

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records, pertinent corporate documents and properties of the Company and its
subsidiaries, and (ii) cause the Company's officers, directors and employees to
supply all information reasonably requested by such Stockholders or any such
underwriter, attorney, accountant or agent in connection with the Registration
Statement, in each case, as is customary for similar due diligence examinations;
provided, however, that all records, information and documents that are
designated in writing by the Company, in good faith, as confidential,
proprietary or containing any material nonpublic information shall be kept
confidential by such Stockholders and any such underwriter, attorney, accountant
or agent (pursuant to an appropriate confidentiality agreement in the case of
any such holder or agent), unless such disclosure is made pursuant to judicial
process in a court proceeding (after first giving the Company an opportunity
promptly to seek a protective order or otherwise limit the scope of the
information sought to be disclosed) or is required by law, or such records,
information or documents become available to the public generally or through a
third party not in violation of an accompanying obligation of confidentiality;
and provided, further, that, if the foregoing inspection and information
gathering would otherwise disrupt the Company's conduct of its business, such
inspection and information gathering shall, to the maximum extent possible, be
coordinated on behalf of the Stockholders and the other parties entitled thereto
by one firm of counsel designed by and on behalf of the majority in interest of
Stockholders and other parties;

     (n) In connection with any underwritten offering, make such representations
and warranties to the Stockholders participating in such underwritten offering
and to the managers, in form, substance and scope as are customarily made by the
Company to underwriters in secondary underwritten offerings;

     (o) In connection with any underwritten offering, obtain opinions of
counsel to the Company (which counsel and opinions (in form, scope and
substance) shall be reasonably satisfactory to the managers) addressed to the
underwriters, covering such matters as are customarily covered in opinions
requested in secondary underwritten offerings (it being agreed that the matters
to be covered by such opinions shall include, without limitation, as of the date
of the opinion and as of the Effective Time of the Registration Statement or
most recent post-effective amendment thereto, as the case may be, the absence
from the Registration Statement and the Prospectus, including any documents
incorporated by reference therein, of an untrue statement of a material fact or
the omission of a material fact required to be stated therein or necessary to
make the statements therein (in the case of the Prospectus, in light of the
circumstances under which they were made) not misleading, subject to customary
limitations);

     (p) In connection with any underwritten offering, obtain "cold comfort"
letters and updates thereof from the independent public accountants of the
Company (and, if necessary, from the independent public accountants of any
subsidiary of the Company or of any business acquired by the Company, in each
case for which financial statements and financial data are, or are required to
be, included in the Registration Statement), addressed to each underwriter
participating in such underwritten offering (if such underwriter has provided
such letter, representations or documentation, if any, required for such cold
comfort letter to be so addressed), in customary form and covering matters of
the type customarily covered in "cold comfort" letters in connection with
secondary underwritten offerings;

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     (q) In connection with any underwritten offering, deliver such documents
and certificates as may be reasonably required by the managers, if any; and

     (r) In the event that any broker-dealer registered under the Exchange Act
shall be an "AFFILIATE" (as defined in Rule 2729(b)(1) of the rules and
regulations of the National Association of Securities Dealers, Inc. (the "NASD
RULES") (or any successor provision thereto)) of the Company or has a "CONFLICT
OF INTEREST" (as defined in Rule 2720(b)(7) of the NASD Rules (or any successor
provision thereto)) and such broker-dealer shall underwrite, participate as a
member of an underwriting syndicate or selling group or assist in the
distribution of any Registrable Securities covered by the Registration
Statement, whether as a holder of such Registrable Securities or as an
underwriter, a placement or sales agent or a broker or dealer in respect
thereof, or otherwise, the Company shall assist such broker-dealer in complying
with the requirements of the NASD Rules, including, without limitation, by (A)
engaging a "QUALIFIED INDEPENDENT UNDERWRITER" (as defined in Rule 2720(b)(15)
of the NASD Rules (or any successor provision thereto)) to participate in the
preparation of the Registration Statement relating to such Registrable
Securities, to exercise usual standards of due diligence in respect thereof and
to recommend the public offering price of such Registrable Securities, (B)
indemnifying such qualified independent underwriter to the extent of the
indemnification of underwriters provided in Section 5 hereof, and (C) providing
such information to such broker-dealer as may be required in order for such
broker-dealer to comply with the requirements of the NASD Rules.

   4. OBLIGATIONS OF THE STOCKHOLDERS

   In connection with the registration of the Registrable Securities, the
Shareholders shall have the following obligations:

     (a) It shall be a condition precedent to the obligations of the Company to
complete the registration pursuant to this Agreement with respect to the
Registrable Securities of a particular Shareholder that such Shareholder shall
furnish to the Company such information regarding itself, the Registrable
Securities held by it and the intended method of disposition of the Registrable
Securities held by it as shall be reasonably required to effect the registration
of such Registrable Securities and shall execute such documents in connection
with such registration as the Company may reasonably request. As least seven
days prior to the first anticipated filing date of the Registration Statement,
the Company shall notify each Shareholder of the information the Company
requires from each such Shareholder (the "REQUESTED INFORMATION") if such
Shareholder elects to have any of its Registrable Securities included in the
Registration Statement. If at least two business days prior to the anticipated
filing date the Company has not received the Requested Information from in
Shareholder (a "NON-RESPONSIVE STOCKHOLDER"), then the Company may file the
Registration Statement without including Registrable Securities of such
Non-Responsive Stockholder and have no further obligations to the Non-Responsive
Stockholder with respect to such registration;

     (b) Each Shareholder by its acceptance of the Registrable Securities agrees
to cooperate with the Company in connection with the preparation and filing of
the Registration Statement hereunder, unless such Stockholder has notified the
Company in writing of its election to exclude all of its Registrable Securities
from the Registration Statement; and

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     (c) Each Shareholder agrees that, upon receipt of any notice from the
Company of the occurrence of any event of the kind described in Section 3(e) or
3(f), it shall immediately discontinue its disposition of Registrable Securities
pursuant to the Registration Statement covering such Registrable Securities
until such Shareholder's receipt of the copies of the supplemented or amended
Prospectus contemplated by Section 3(e) and, if so directed by the Company, such
Shareholder shall deliver to the Company (at the expense of the Company) or
destroy (and deliver to the Company a certificate of destruction) all copies in
such Shareholder's possession, of the Prospectus covering such Registrable
Securities current at the time of receipt of such notice.

   5. EXPENSES OF REGISTRATION

   The Company shall pay all expenses, other than underwriting discounts and
commissions, incurred in connection with registrations, filings or
qualifications pursuant to Section 3, including, without limitation, all
registration, listing, and qualifications fees, printing and engraving fees,
accounting fees, and the fees and disbursements of counsel for the Company. The
expenses paid by the Company will not include any advisory fees incurred by the
Stockholders, other than the reasonable fees and expenses of a single counsel
for the Stockholders, up to a maximum of $15,000.

   6. INDEMNIFICATION AND CONTRIBUTION

     (a) The Company shall indemnify and hold harmless each Shareholder and each
underwriter, if any, which facilitates the disposition of Registrable
Securities, and each of their respective officers and directors and each person
who controls such Shareholder or underwriter within the meaning of Section 15 of
the Securities Act or Section 20 of the Exchange Act (each such person being
sometimes hereinafter referred to as an "INDEMNIFIED PERSON") from and against
any losses, claims, damages or liabilities, joint or several, to which such
Indemnified Person may become subject under the Securities Act or otherwise,
insofar as such losses, claims, damages or liabilities (or actions in respect
thereof) arise out of or are based upon an untrue statement or alleged untrue
statement of a material fact contained in any Registration Statement or an
omission or alleged omission to state therein a material fact required to be
stated therein or necessary to make the statements therein, not misleading, or
arise out of or are based upon an untrue statement or alleged untrue statement
of a material fact contained in any Prospectus or an omission or alleged
omission to state therein a material fact required to be stated therein or
necessary to make the statements therein, in the light of the circumstances
under which they were made, not misleading; and the Company hereby agrees to
reimburse such Indemnified Person for all reasonable legal and other expenses
incurred by them in connection with investigating or defending any such action
or claim as and when such expenses are incurred; provided, however, that the
Company shall not be liable to any such Indemnified Person in any such case to
the extent that any such loss, claim, damage or liability arises out of or is
based upon (i) an untrue statement or alleged untrue statement made in, or an
omission or alleged omission from, such Registration Statement or Prospectus in
reliance upon and in conformity with written information furnished to the
Company by such Indemnified Person expressly for use therein or (ii) in the case
of the occurrence of an event of the type specified in Section 3(e), the use by
the Indemnified Person of an outdated or defective Prospectus after the Company
has provided to such Indemnified Person an updated Prospectus correcting the
untrue statement or alleged untrue statement or omission or alleged omission
giving rise to such loss, claim, damage or liability.

                                      -10-

<PAGE>   11

     (b) INDEMNIFICATION BY THE STOCKHOLDERS AND UNDERWRITERS. Each Stockholder
agrees, as a consequence of the inclusion of any of its Registrable Securities
in a Registration Statement, and each underwriter, if any, which facilitates the
disposition of Registrable Securities shall agree, as a consequence of
facilitating such disposition of Registrable Securities, severally and not
jointly, to (i) indemnify and hold harmless the Company, its directors
(including any person who, with his or her consent, is named in the Registration
Statement as a director nominee of the Company), its officers who sign any
Registration Statement and each person, if any, who controls the Company within
the meaning of either Section 15 of the Securities Act or Section 20 of the
Exchange Act, against any losses, claims, damages or liabilities to which the
Company or such other persons may become subject, under the Securities Act or
otherwise, insofar as such losses, claims, damages or liabilities (or actions in
respect thereof) arise out of or are based upon an untrue statement or alleged
untrue statement of a material fact contained in such Registration Statement or
Prospectus or arise out of or are based upon the omission or alleged omission to
state therein a material fact required to be stated therein or necessary to make
the statements therein (in light of the circumstances under which they were
made, in the case of the Prospectus), not misleading, in each case to the
extent, but only to the extent, that such untrue statement or alleged untrue
statement or omission or alleged omission was made in reliance upon and in
conformity with written information furnished to the Company by such holder or
underwriter expressly for use therein; provided, however, that no Stockholder or
underwriter shall be liable under this Section 6(b) for any amount in excess of
the net proceeds paid to such Stockholder or underwriter in respect of shares
sold by it, and (ii) reimburse the Company for any legal or other expenses
incurred by the Company in connection with investigating or defending any such
action or claim as such expenses are incurred.

     (c) NOTICE OF CLAIMS, ETC. Promptly after receipt by a party seeking
indemnification pursuant to this Section 6 (an "INDEMNIFIED PARTY") of written
notice of any investigation, claim, proceeding or other action in respect of
which indemnification is being sought (each, a "CLAIM"), the Indemnified Party
promptly shall notify the party against whom indemnification pursuant to this
Section 6 is being sought (the "INDEMNIFYING PARTY") of the commencement
thereof; but the omission to so notify the Indemnifying Party shall not relieve
it from any liability that it otherwise may have to the Indemnified Party,
except to the extent that the Indemnifying Party is materially prejudiced and
forfeits substantive rights and defenses by reason of such failure. In
connection with any Claim as to which both the Indemnifying Party and the
Indemnified Party are parties, the Indemnifying Party shall be entitled to
assume the defense thereof. Notwithstanding the assumption of the defense of any
Claim by the Indemnifying Party, the Indemnified Party shall have the right to
employ separate legal counsel and to participate in the defense of such Claim,
and the Indemnifying Party shall bear the reasonable fees, out-of-pocket costs
and expenses of such separate legal counsel to the Indemnified Party if (and
only if): (x) the Indemnifying Party shall have agreed to pay such fees, costs
and expenses, (y) the Indemnified Party and the Indemnifying Party shall
reasonably have concluded that representation of the Indemnified Party by the
Indemnifying Party by the same legal counsel would not be appropriate due to
actual or, as reasonably determined by legal counsel to the Indemnified Party,
potentially differing interests between such parties in the conduct of the
defense of such Claim, or if there may be legal defenses available to the
Indemnified Party that are in addition to or disparate from those available to
the Indemnifying Party, or (z) the Indemnifying Party shall have failed to
employ legal counsel reasonably satisfactory to the Indemnified Party within a
reasonable period of time after notice of the

                                      -11-

<PAGE>   12

commencement of such Claim. If the Indemnified Party employs separate legal
counsel in circumstances other than as described in clauses (x), (y) or (z)
above, the fees, costs and expenses of such legal counsel shall be borne
exclusively by the Indemnified Party. Except as provided above, the Indemnifying
Party shall not, in connection with any Claim in the same jurisdiction, be
liable for the fees and expenses of more than one firm of counsel for the
Indemnified Party (together with appropriate local counsel). The Indemnified
Party shall not, without the prior written consent of the Indemnifying Party
(which consent shall not unreasonably be withheld), settle or compromise any
Claim or consent to the entry of any judgment that does not include an
unconditional release of the Indemnifying Party from all liabilities with
respect to such Claim or judgment.

     (d) CONTRIBUTION. If the indemnification provided for in this Section 6 is
unavailable to or insufficient to hold harmless an Indemnified Person under
subsection (a) or (b) above in respect of any losses, claims, damages or
liabilities (or actions in respect thereof) referred to therein, then each
Indemnifying Party shall contribute to the amount paid or payable by such
Indemnified Party as a result of such losses, claims, damages or liabilities (or
actions in respect thereof) in such proportion as is appropriate to reflect the
relative fault of the Indemnifying Party and the Indemnified Party in connection
with the statements or omissions which resulted in such losses, claims, damages
or liabilities (or actions in respect thereof), as well as any other relevant
equitable considerations. The relative fault of such Indemnifying Party and
Indemnified Party shall be determined by reference to, among other things,
whether the untrue or alleged untrue statement of a material fact or omission or
alleged omission to state a material fact relates to information supplied by
such Indemnifying Party or by such Indemnified Party, and the parties' relative
intent, knowledge, access to information and opportunity to correct or prevent
such statement or omission. The parties hereto agree that it would not be just
and equitable if contribution pursuant to this Section 6(d) were determined by
pro rata allocation (even if the Stockholders or any underwriters were treated
as one entity for such purpose) or by any other method of allocation which does
not take account of the equitable considerations referred to in this Section
6(d). The amount paid or payable by an Indemnified Party as a result of the
losses, claims, damages or liabilities (or actions in respect thereof) referred
to above shall be deemed to include any legal or other fees or expenses
reasonably incurred by such Indemnified Party in connection with investigating
or defending any such action or claim. No person guilty of fraudulent
misrepresentation (within the meaning of Section 11(f) of the Securities Act)
shall be entitled to contribution from any person who was not guilty of such
fraudulent misrepresentation. The obligations of the Stockholders and any
underwriters in this Section 6(d) to contribute shall be several in proportion
to the percentage of Registrable Securities registered or underwritten, as the
case may be, by them and not joint.

     (e) Notwithstanding any other provision of this Section 6, in no event
shall any (i) Stockholder be required to undertake liability to any person under
this Section 6 for any amounts in excess of the dollar amount of the proceeds to
be received by such Stockholder from the sale of such Stockholder's Registrable
Securities (after deducting any fees, discounts and commissions applicable
thereto) pursuant to any Registration Statement under which such Registrable
Securities are to be registered under the Securities Act and (ii) underwriter be
required to undertake liability to any Person hereunder for any amounts in
excess of the aggregate discount, commission or other compensation payable to
such underwriter with respect to the Registrable Securities underwritten by it
and distributed pursuant to the Registration Statement.

                                      -12-

<PAGE>   13

     (f) The obligations of the Company under this Section 6 shall be in
addition to any liability which the Company may otherwise have to any
Indemnified Person and the obligations of any Indemnified Person under this
Section 6 shall be in addition to any liability which such Indemnified Person
may otherwise have to the Company. The remedies provided in this Section 6 are
not exclusive and shall not limit any rights or remedies which may otherwise be
available to an indemnified party at law or in equity.

  7. RULE 144

  With a view to making available to the Shareholders the benefits of Rule
144 under the Securities Act or any other similar rule or regulation of the
Commission that may at any time permit the Stockholders to sell securities of
the Company to the public without registration ("RULE 144"), the Company agrees
to use its best efforts to:

     (a) comply with the provisions of paragraph (c) (1) of Rule 144; and

     (b) file with the Commission in a timely manner all reports and other
documents required to be filed by the Company pursuant to Section 13 or 15(d)
under the Exchange Act; and, if at any time it is not required to file such
reports but in the past had been required to or did file such reports, it will,
upon the request of any Stockholder, make available other information as
required by, and so long as necessary to permit sales of, its Registrable
Securities pursuant to Rule 144.

  8. LOCK-UP

  Each Stockholder may not sell, make any short sale of, pledge, grant any
option to purchase, or otherwise transfer or dispose of any of the Registerable
Securities held by such Holder at any time prior to August 31, 2000; provided
however that the Stockholders of the Company are agreeing to the foregoing
restriction in reliance on the Company's representation that holders of a
majority of the outstanding restricted shares of capital stock of the Company
(as defined below) are subject to similar restrictions; to the extent that and
at such time as a majority of the outstanding shares of capital stock of the
Company which have not been resold on the public market are no longer subject to
similar restrictions, the Company shall notify the Stockholders as soon as
practicable and the foregoing restriction shall no longer apply to the
Stockholders it. For purposes of the foregoing, "restricted" shares means all
shares of capital stock which have not been sold to the public pursuant to a
registration statement under the Act or pursuant to Rule 144 or Rule 701 under
the Act. The Company may impose stop-transfer instructions with respect to the
shares (or securities) subject to the foregoing restriction until the end of the
application of such restriction. Transfers to immediate family members of a
Stockholder, or to beneficial trusts or other estate planning vehicles shall be
exempt from the foregoing restriction.

  9. ASSIGNMENT

  The rights to have the Company register Registrable Securities pursuant to
this Agreement shall be automatically assigned by the Shareholders to any
transferee of all or any portion of the Registrable Securities, but only if: (a)
the Shareholder agrees in writing with the transferee or assignee to assign such
rights, and a copy of such agreement is furnished to the Company within a

                                      -13-

<PAGE>   14

reasonable time after such assignment, (b) the Company is, within a reasonable
time after such transfer or assignment, furnished with written notice of (i) the
name and address of such transferee or assignee and (ii) the securities with
respect to which such registration rights are being transferred or assigned, (c)
immediately following such transfer or assignment, the securities so transferred
or assigned to the transferee or assignee constitute Restricted Securities, and
(d) at or before the time the Company received the written notice contemplated
by clause (b) of this sentence the transferee or assignee agrees in writing with
the Company to be bound by all of the provisions contained herein.

     10. AMENDMENT AND WAIVER

     Any provision of this Agreement may be amended and the observance thereof
may be waived (either generally or in a particular instance and either
retroactively or prospectively), only with the written consent of the Company
and Stockholders who hold a majority-in-interest of the Registrable Securities.
Any amendment or waiver effected in accordance with this Section 9 shall be
binding upon each Stockholder and the Company.

     11. MISCELLANEOUS

        (a) A person or entity shall be deemed to be a holder of Registrable
Securities whenever such person or entity owns of record such Registrable
Securities. If the Company receives conflicting instructions, notices or
elections from two or more persons or entities with respect to the same
Registrable Securities, the Company shall act upon the basis of instructions,
notice or election received from the registered owner of such Registrable
Securities.

        (b) Except as may be otherwise provided herein, any notice or other
communication or delivery required or permitted hereunder shall be in writing
and shall be delivered personally or sent by certified mail, postage prepaid, or
by a nationally recognized overnight courier service, and shall be deemed given
when so delivered personally or by overnight courier service, or, if mailed,
three days after the date of deposit in the United States mails, as follows:

                      (i)         to the Company, to:
                                  Popmail.com, Inc.
                                  4801 West 81st Street, Suite 112
                                  Bloomington, MN 55437
                                  Attention: Stephen D. King
                                  (612) 837-9917
                                  (612) 837-9916 (Fax)

                                  with a copy to:
                                  Maslon Edelman Borman & Brand, LLP
                                  3300 Norwest Center
                                  90 South Seventh Street
                                  Minneapolis, MN 55402
                                  Attention:  William M. Mower, Esq.

                                      -14-

<PAGE>   15

                                  (612) 672-8358
                                  (612) 672-8397 (Fax)

                      (ii)        if to a Stockholder, at such
                                  Stockholder's address as set forth
                                  on the signature page hereof, or
                                  such other address as the
                                  Stockholder shall have supplied to
                                  the Company.

The Company, or any Stockholder may change the foregoing address by notice given
pursuant to this Section 10(c).

     (c) Failure of any party to exercise any right or remedy under this
Agreement or otherwise, or delay by a party in exercising such right or remedy,
shall not operate as a waiver thereof.

     (d) This Agreement shall be governed by and interpreted in accordance with
the laws of the State of Delaware.

     (e) The remedies provided in this Agreement are cumulative and not
exclusive of any remedies provided by law. If any term, provision, covenant or
restriction of this Agreement is held by a court of competent jurisdiction to be
invalid, illegal, void or unenforceable, the remainder of the terms, provisions,
covenants and restrictions set forth herein shall remain in full force and
effect and shall in no way be affected, impaired or invalidated, and the parties
hereto shall use their best efforts to find and employ an alternative means to
achieve the same or substantially the same result as that contemplated by such
term, provision, covenant or restriction. It is hereby stipulated and declared
to be the intention of the parties that they would have executed the remaining
terms, provisions, covenants and restrictions without including any of such that
may be hereafter declared invalid, illegal, void or unenforceable.

     (f) The Company shall not enter into any agreement with respect to its
securities that is inconsistent with the rights granted to the holders of
Registrable Securities in this Agreement or otherwise conflicts with the
provisions hereof or adversely affects the rights of the Stockholders under
Section 2(d) hereof. The Company is not currently a party to any agreement
granting any registration rights with respect to any of its securities to any
person which conflicts with the Company's obligations hereunder or gives any
other party the right to include any securities in any Registration Statement
filed pursuant hereto, other than pursuant to certain agreements Parent has
provided to counsel for the Company, except for such rights and conflicts as
have been irrevocably waived. Without limiting the generality of the foregoing,
without the written consent of the holders of a majority in interest of the
Registrable Securities, the Company shall not grant to any person the right to
request it to register any of its securities under the Securities Act unless the
rights so granted are subject in all respect to the prior rights of the holders
of Registrable Securities set forth herein, and are not otherwise in conflict or
inconsistent with the provisions of this Agreement. The restrictions on the
Company's rights to grant registration rights under this paragraph shall
terminate on the date the Registration Statement to be filed pursuant to Section
2(a) is declared effective by the Commission.

                                      -15-

<PAGE>   16

     (g) This Agreement and the Reorganization Agreement, constitute the entire
agreement among the parties hereto with respect to the subject matter hereof.
There are no restrictions, promises, warranties or undertakings, other than
those set forth or referred to herein. This Agreement and the Reorganization
Agreement, supersede all prior agreements and undertakings among the parties
hereto with respect to the subject matter hereof.

     (h) Subject to the requirements of Section 8 hereof, this Agreement shall
inure to the benefit of and be binding upon the successors and assigns of each
of the parties hereto.

     (i) All pronouns and any variations thereof refer to the masculine,
feminine or neuter, singular or plural, as the context may require.

     (j) The headings in this Agreement are for convenience of reference only
and shall not limit or otherwise affect the meaning thereof.

     (k) This Agreement may be executed in two or more counterparts, each of
which shall be deemed an original but all of which shall constitute one and the
same agreement. A facsimile transmission of this signed Agreement shall be legal
and binding on all parties hereto.

                                      -16-

<PAGE>   17

         IN WITNESS WHEREOF, the parties have caused this Agreement to be duly
executed and delivered as of the date first above written.

COMPANY:                                  POPMAIL.COM, INC.

                                          By: /s/ Stephen D. King
                                             ----------------------------------
                                          Name:  Stephen D. King
                                          Title:  Chief Executive Officer

STOCKHOLDERS:                             Name:/s/[Each stockholder of IZ.com
                                                  Incorporated]
                                               --------------------------------
                                          By:
                                             ----------------------------------
                                          Title:
                                                -------------------------------
                                          Address:
                                                  -----------------------------
                                                  -----------------------------

                                          Facsimile:
                                                    ---------------------------

                                      -17-<PAGE>   1
                                                                     EXHIBIT 4.1

================================================================================

                             NABORS HOLDING COMPANY
                (successor by merger of POOL ENERGY SERVICES CO.)

                                       and

                           THE GUARANTORS NAMED HEREIN

                                       and

                             NABORS INDUSTRIES, INC.

                                  $150,000,000

                    8 5/8% Senior Subordinated Notes due 2008

                          THIRD SUPPLEMENTAL INDENTURE

                          Dated as of February 14, 2000

                                 HSBC BANK USA,

                                   AS TRUSTEE

<PAGE>   2

         This THIRD SUPPLEMENTAL INDENTURE, dated as of February 14, 2000, is
among Nabors Holding Company, a Delaware corporation (successor by merger of
Pool Energy Services Co., a Texas corporation) ("NHC" or the "Company"), Nabors
Industries, Inc. ("Nabors" or the "Parent Guarantor"), a Delaware corporation
and parent corporation of the Company, Associated Petroleum Services, Inc.,
International Air Drilling Company, Kuukpik-Pool Arctic Alaska, Pool Alaska,
Inc., Pool Americas, Inc., Pool-Australia, Inc., Pool Company, Pool Company
Texas, Ltd., Pool International, Inc., Pool Well Services Co., PCNV, Inc., PTX,
Inc., Sea Mar, Inc. and Sea Mar Management, Inc. (collectively referred to
herein as the "Subsidiary Guarantors") and HSBC Bank USA (formerly known as
Marine Midland Bank), as trustee (the "Trustee").

                                    RECITALS

         WHEREAS, Pool Energy Services Co., a Texas corporation ("PESC"), the
subsidiary guarantors referred to therein and the Trustee entered into an
Indenture, dated as of March 31, 1998, as amended by the First Supplemental
Indenture, dated as of March 31, 1998 (as amended, the "First Indenture"),
pursuant to which PESC issued $150,000,000 in aggregate principal amount of 8
5/8% Senior Subordinated Notes due 2008 (the "Notes"), the payment of which was
guaranteed by such subsidiary guarantors;

         WHEREAS, on November 24, 1999 (i) Starry Acquisition Corp. merged with
and into PESC, and as a result PESC became an indirectly wholly-owned subsidiary
of Nabors and (ii) PESC changed its state of incorporation and name through a
merger with and into NHC (such transactions are collectively referred to as the
"Acquisition"), in each case in accordance with Section 5.01 of the First
Indenture;

         WHEREAS, in connection with the Acquisition, certain subsidiary
guarantors named in the First Indenture merged, dissolved and/or engaged in
transactions with an affiliate (together with the Acquisition, the
"Transactions"), in each case in accordance with the terms of the First
Indenture;

         WHEREAS, the Company, the Subsidiary Guarantors and the Trustee entered
into a Second Supplemental Indenture, dated as of December 1, 1999 (together
with the First Indenture, the "Indenture") to, among other things, (i) reflect
the Acquisition and the change of the name of the issuer of the Notes to "Nabors
Holding Company" and the change of its jurisdiction of incorporation to
Delaware, (ii) provide for the assumption or reaffirmation of the obligations of
PESC to the Holders by the Company, and (iii) reflect the Transactions and
provide for the assumption and/or ratification of the obligations of the
applicable subsidiary guarantors by the applicable surviving entities, in each
case in accordance with the terms of the Indenture;

         WHEREAS, Section 9.02 of the Indenture provides that, with the written
consent of the Holders of at least a majority of the principal amount of the
Notes then outstanding, the Company, the Subsidiary Guarantors and the Trustee
may enter into one or more indentures supplemental to the Indenture for the
purpose of adding any provisions to or changing or eliminating any of the
provisions of the Indenture or modifying the rights of the Holders of the Notes,
subject to certain exceptions specified in Section 9.02 of the Indenture;

         WHEREAS, the Company desires to and has requested that the Trustee
enter into this Third Supplemental Indenture to, among other things, (i) provide
for the guarantee of the obligations of the Company by the Parent Guarantor;
(ii) provide for the release of the guarantees of the Subsidiary Guarantors; and
(iii) amend and/or eliminate certain provisions of the Indenture and the Note;

         WHEREAS, the Holders of in excess of a majority of the principal amount
at the stated maturity of the outstanding Notes have duly consented to the
execution and delivery of this Third Supplemental Indenture, pursuant to the
Change of Control Offer and Consent Solicitation Statement of the Company, dated
December 24, 1999;

         WHEREAS, the execution and delivery of this Third Supplemental
Indenture has been duly authorized by the appropriate resolutions of the Board
of Directors of the Company, the Parent Guarantor and each of the Subsidiary
Guarantors; and

                                  Page 2 of 11
<PAGE>   3
         WHEREAS, all conditions and requirements necessary to make this Third
Supplemental Indenture a valid, binding and legal instrument enforceable in
accordance with its terms have been performed and fulfilled by the parties
hereto and the execution and delivery thereof have been in all respects duly
authorized by the parties hereto.

         NOW, THEREFORE, in consideration of the above premises, each party
hereto agrees, for the benefit of the other and for the equal and ratable
benefit of the Holders of the Notes, as follows:

                                   ARTICLE I
                       ADDITION AND RELEASE OF GUARANTEES

         Section 1.1. Addition of Guarantor. The Parent Guarantor
unconditionally guarantees the obligations of the Company under the Indenture
and the Notes and agrees to be subject to the obligations of a Guarantor under
the Indenture and the Notes, each as modified hereby, in accordance with the
provisions thereof.

         Section 1.2. Release of Subsidiary Guarantors. The Subsidiary
Guarantors are hereby fully and finally released and relieved of any and all
obligations under the Indenture, the Notes and any Note Guarantees.

                                   ARTICLE II
                           AMENDMENTS TO THE INDENTURE

         Section 2.1. Amendment to the Introductory Paragraph and Change of
Name. The introductory paragraph of the Indenture is amended by being replaced
in its entirety with the following:

                  "INDENTURE, dated as of March 31, 1998, by and among Nabors
         Holdings Company (as further defined below, the 'Company'), Nabors
         Industries, Inc. (as further defined below, the 'Parent Guarantor') and
         HSBC Bank USA, a New York banking corporation and trust company, as
         trustee (the 'Trustee')."

         Section 2.2. Amendments to Article 1 of the Indenture. For all purposes
of the Indenture, the following amendments shall be made to Article 1 thereof
and elsewhere within the Indenture and the Notes as the context requires:

                  (1) The terms "Subsidiary Guarantor" and "Subsidiary
Guarantors" are amended to read "Parent Guarantor" and all verbs or verb tenses
following such terms and articles preceding such terms as well as signature
blocks shall be deemed to be amended as appropriate to reflect such changes.

                  (2) The terms "Guarantees" and "Guarantors" shall be deemed to
mean "Guarantee" and "Guarantor", respectively, as the context requires and all
verbs or verb tenses following such terms and articles preceding such terms
shall be deemed to be amended to reflect such changes.

                  (3) The term "Company" or "Company's" is hereby deleted in its
entirety from the following definitions contained in Section 1.01 of the
Indenture and replaced with "Parent Guarantor" or "Parent Guarantor's", as
applicable:

                           (a)      Acquired Indebtedness;
                           (b)      Attributable Indebtedness;
                           (c)      Board Resolution;
                           (d)      Cash Equivalents;
                           (e)      Corporate Trust Office;
                           (f)      Designated Senior Indebtedness;
                           (g)      Foreign Subsidiary;
                           (h)      Indebtedness;
                           (i)      Independent Director;
                           (j)      Officer;
                           (k)      Opinion of Counsel;
                           (l)      Permitted Junior Securities;

                                  Page 3 of 11
<PAGE>   4

                           (m)      Permitted Liens;
                           (n)      Refinancing Indebtedness; (o) Restricted
                                    Investment;
                           (p)      Restricted Subsidiary;
                           (q)      Senior Indebtedness;
                           (r)      Senior Subordinated Indebtedness;
                           (s)      Significant Subsidiary;
                           (t)      Subordinated Indebtedness;
                           (u)      Subsidiary;
                           (v)      Unrestricted Subsidiary; and
                           (w)      Wholly-Owned Restricted Subsidiary.

                  (4) The following terms and the definitions thereof, as listed
in Sections 1.01 and 1.02 of the Indenture, are deleted in their entireties
together will all references thereto and any related syntax, as case may be, in
the Indenture:

                           (a)      Affiliate Transaction;
                           (b)      Asset Sale;
                           (c)      Asset Sale Offer;
                           (d)      Asset Sale Offer Amount;
                           (e)      Asset Sale Trigger Date;
                           (f)      Consolidated Amortization Expense;
                           (g)      Consolidated Depreciation Expense;
                           (h)      Consolidated Income Tax Expense;
                           (i)      Consolidated Interest Coverage Ratio;
                           (j)      Consolidated Interest Expense;
                           (k)      Consolidated Net Income;
                           (l)      Coverage Ratio Incurrence Condition;
                           (m)      EBITDA; (n) Excess Proceeds;
                           (o)      Existing Indebtedness;
                           (p)      Independent Financial Advisor;
                           (q)      Net Available Proceeds;
                           (r)      Net Proceeds Deficiency;
                           (s)      Net Proceeds Offer Period;
                           (t)      Net Proceeds Purchase Date;
                           (u)      Offered Price;
                           (v)      Payment Amount;
                           (w)      Payment Restriction;
                           (x)      Related Business;
                           (y)      Related Business Investment;
                           (z)      Related Party Agreement;
                           (aa)     Replacement Facility
                           (bb)     Restricted Debt Payment; and
                           (cc)     Restricted Payment.

                  (5) The definition of "Change of Control" is amended by (a)
inserting the following phrase at the end of paragraph (i): "(other than such a
change resulting from a reorganization transaction which does not result in such
a change in the ultimate beneficial ownership of the Parent Guarantor)" and (b)
deleting all references to the term "Company" located therein and replacing them
with "Parent Guarantor".

                  (6) The definition of "Credit Agreement" is deleted in its
entirety and replaced with the following:

                           "Credit Agreement" means the Credit Agreement, dated
         as of September 7, 1997, by and among the Parent Guarantor, the
         subsidiary borrowers named therein, Bank of America National Trust and
         Savings Association, as administrative agent, Wells Fargo Bank (Texas),
         National Association, as

                                  Page 4 of 11
<PAGE>   5

         documentation agent, and BancAmerica Securities, Inc., as arranger,
         together with any additional guarantees thereof and security
         agreements, as any of the foregoing may be subsequently amended,
         restated, refinanced, or replaced from time to time, and shall include
         agreements in respect of Hedging Obligations designed to protect
         against fluctuations in interest rates and entered into with respect to
         loans thereunder."

                  (7) In addition to the amendments provided in paragraph (3) of
this Section, the definition of "Designated Senior Indebtedness" is amended by
deleting clause (i) in its entirety through and including the symbol "(ii)" and
replacing it with the following:

                  "Designated Senior Indebtedness" means (i) Indebtedness
         incurred or permitted to be incurred under the Credit Agreement; (ii)
         Indebtedness incurred pursuant to the Indenture, dated as of March 1,
         1999 (as supplemented by Supplemental No. 1 thereto dated as of March
         1, 1999), between the Parent Guarantor and Norwest Bank Minnesota,
         National Association, as trustee; and (iii)"

                  (8) The definition of "Equity Offering" is amended by: (a)
inserting the clause "Parent Guarantor or the" in front of the first occurrence
of the term "Company" therein; and (b) replacing the second occurrence of the
term "Company" therein with "Parent Guarantor."

                  (9) The definition of "Guarantor" is deleted in its entirety
and replaced with:

                  "'Guarantor' means the Parent Guarantor."

                  (10) The term and definition of "Non-Recourse Purchase Money
Indebtedness" is deleted in its entirety and replaced with the definition set
forth below. In addition, all references to "Non-Recourse Purchase Money
Indebtedness" in the Indenture are replaced with "Non-Recourse Indebtedness."

                  "'Non-Recourse Indebtedness' means Indebtedness of the Parent
         Guarantor or any of its Subsidiaries to the extent that such
         Indebtedness is non-recourse to the Parent Guarantor or any of its
         Subsidiaries or any of their respective assets other than the assets
         specifically secured thereby."

                  (11) The definition of "Offer" and "Offer Period" are amended
by deleting the references to "or a Net Proceeds Offer, as the context requires"
located therein.

                  (12) The following definition of "Parent Guarantor" is
inserted in the appropriate alphabetical order:

                  "'Parent Guarantor' means Nabors Industries, Inc., a Delaware
         corporation and parent corporation of the Company."

                  (13) The definition of "Permitted Indebtedness" is amended by:

                           (a) deleting all references to "Company" in
                  paragraphs (vi) and (vii) thereof replacing them, in each
                  instance, with: "Parent Guarantor";

                           (b) deleting paragraph (i) thereof in its entirety
                  and replacing it with the following:

                  "(i) Indebtedness of the Parent Guarantor and any Subsidiary
         thereof under the Credit Agreement;";

                           (c) deleting paragraph (iii) thereof in its entirety
                  and replacing it with the following:

                  "(iii) Indebtedness of the Parent Guarantor and/or its
         Subsidiaries existing on the date of the Third Supplemental Indenture
         hereto;";

                           (d) deleting the reference to "or Indebtedness
                  permitted by Section 4.07" from paragraph

                                  Page 5 of 11
<PAGE>   6

                  (iv) thereof;

                           (e) deleting paragraph (v) thereof in its entirety
                  and replacing it with the following:

                  "(v) Indebtedness of the Company to the Parent Guarantor and
         Indebtedness of the Parent Guarantor to the Company;";

                           (f) amending paragraph (ix) by deleting the terms
                  "$10.0 million" and "$20.0 million" and replacing them with:
                  "$30.0 million" and "$60.0 million", respectively; and

                           (g) deleting paragraph (x) thereof in its entirety
                  and replacing it with the following:

                  "(x) Acquired Indebtedness."

                  (14) In addition to the amendments provided in paragraph (3)
of this Section, the definition of "Permitted Liens" is amended by (a) inserting
at the end of paragraph (i) thereof: "or as of the date of the Third
Supplemental Indenture hereto", (b) inserting ", (ix)" between the terms "(i)"
and "and" in paragraph (iv), (c) deleting paragraph (xii) in its entirety and
replacing it with the following: "(xii) Liens securing Non-Recourse
Indebtedness;", and (d) deleting the entirety of paragraph (xiii) after the
first instance of the term "Acquired Indebtedness."

                  (15) In addition to the amendments provided in paragraph (3)
of this Section, the definition of "Refinancing Indebtedness" is amended by
inserting the term "150% of" after the clauses: (a) "in a principal amount not
in excess of"; and (b) "with a maximum commitment not to exceed".

                  (16) In addition to the amendments provided in paragraph (3)
of this Section, the definition of "Senior Indebtedness" is amended by: (a)
inserting after the words "Issue Date" located therein: ", as of the date of the
Third Supplemental Indenture hereto"; (b) deleting the reference to "not
prohibited by Section 4.07" located in clause (iii) thereof; (c) deleting the
word "and" which immediately precedes the figures "(v)" located therein; and (d)
inserting the following as clause (vi) after the provisions of clause (v):

                  ";and (vi) the principal of and interest on and all other
         Indebtedness and Obligations related to Designated Senior
         Indebtedness."

                  (17) The definition of "Significant Subsidiary" is amended by
deleting the reference to: ", except all references to '10 percent' in such
definition shall be changed to '2 percent'".

                  (18) The definition of "Unrestricted Subsidiary" is amended by
deleting from the third sentence thereof, the following phrases: (i) the phrase
that begins with: "and any such designation" and ends with "the dates of such
designation,"; and (ii) the phrase that begins with: "and the incurrence" and
ends with "Coverage Ratio Incurrence Condition and (y)".

         Section 2.3. Amendments to Article 2 of the Indenture. Section 2.13 is
amended by deleting the reference to "Sections 4.15 or 4.16" and replacing it
with "Section 4.15."

         Section 2.4. Amendments to Article 3 of the Indenture. For all purposes
of the Indenture, the following amendments shall be made to Article 3:

                  (1) Section 3.01 is amended by deleting the references to
"Section 4.15 or 4.16" and "Section 4.15 or 4.16, as the case may be" and
replacing them with "Section 4.15."

                  (2) Section 3.08(a) is amended by: (a) deleting the clause "or
Asset Sale Trigger Date" from the first sentence thereof; (b) deleting, in all
instances, the clause "or 4.16, as the case may be"; and (c) deleting the clause
"or Asset Sale, as the case may be" from clause (1) of paragraph (a).

                                  Page 6 of 11
<PAGE>   7

                  (3) Section 3.08(b) is amended by deleting the text of clause
(i)(y) thereof and inserting in its place the following: "[Intentionally
Omitted]".

                  (4) Section 3.08(d) is amended by deleting from clause (i)
thereof the phrase "or Offered Price, as the case may be".

                  (5) Section 3.08(f) is amended by deleting the clause "Section
3.08, Section 4.15 or Section 4.16" and replacing it with "Section 3.08 or
Section 4.15".

         Section 2.5. Amendments to Article 4 of the Indenture. For all purposes
of the Indenture, the following amendments shall be made to Article 4: (1)
Sections 4.05, 4.07, 4.08, 4.09, 4.10, 4.13, 4.16 and 4.17 of the Indenture are
hereby deleted in their entireties, together with any references thereto in the
Indenture. "[Intentionally Omitted]" shall be inserted in place of the text of
such Sections; and (2) Section 4.02 is amended by: (a) deleting both references
to "the Company and the Subsidiary Guarantors" located in the first sentence
thereof, and (b) inserting, after the reference to "Exchange Act" located in the
first sentence thereof, the following: "(including therein any summary or other
information with respect to the Company as may be required thereby taking into
account the guarantee by the Parent Guarantor) if the Parent Guarantor was".

         Section 2.6. Amendment to Article 5 of the Indenture. Each and every
occurrence of the term "Company" in Section 5.01 of the Indenture is hereby
amended to read: "Parent Guarantor" and the text of clauses (x)(2) and (y)
thereof are deleted in their entireties and, in each instance, replaced with
"[Intentionally Omitted]".

         Section 2.7. Amendment to Article 6 of the Indenture. For all purposes
of the Indenture, the following amendments shall be made to Article 6: (1)
Section 6.01 is amended by (a) deleting from paragraph (a)(iii) thereof the
reference to: "or a Net Proceeds Offer" and (b) deleting the reference to
"Sections 4.15 and 4.16, respectively" and replacing it with "Section 4.15"; (2)
Section 6.01 is amended by deleting paragraphs (a)(v) and (vi) thereof in their
entireties and replacing them with the following: "[Intentionally Omitted]"; (3)
Section 6.01 is amended by deleting from paragraph (a)(viii) the word "Company"
and replacing it with "Parent Guarantor"; (4) Section 6.02 is amended by
inserting in paragraph (a) and (b) thereof the following clause after each
occurrence of the word "Company": "or the Parent Guarantor" in all instances
therein. (5) Section 6.10 is amended by inserting immediately after the clause
"to the Company", the following: "or the Parent Guarantor". (6) Section 6.12 of
the Indenture is deleted in its entirety, together with any references thereto.
"[Intentionally Omitted]" shall be inserted in place of the text in such
Section.

         Section 2.8. Amendments to Article 11 of the Indenture. For all
purposes of the Indenture, the following amendments shall be made to Article 11:

                  (1) Sections 11.04 and 11.05 of the Indenture are deleted in
their entireties, together with any references thereto. "[Intentionally
Omitted]" shall be inserted in place of the text of such Sections.

                  (2) Section 11.06 of the Indenture is amended by:

                                  Page 7 of 11
<PAGE>   8

                  (i) deleting all references to "Subsidiary Guarantor" or
         "Subsidiary Guarantors" located therein, including the reference in the
         heading thereof, and replacing them with "Company";

                  (ii) inserting the word "not" between the words "may" and
         "consolidate" contained in the second line thereof;

                  (iii) making all conforming changes required to articles,
         verbs and verb tenses;

                  (iv) amending paragraph (a) by deleting the phrase, "subject
         to the provisions of Section 11.07 hereof," and references to, "this
         Indenture and such Subsidiary Guarantor's Note Guarantee" located in
         the last line of paragraph (a) thereof and replacing it with "and this
         Indenture.";

                  (v) deleting from paragraph (c) thereof, the phrase beginning
         with the word "immediately" and ending with the word "met"; and

                  (vi) deleting the last paragraph of Section 11.06 in its
         entirety and replacing it with following:

                           "Except as set forth in Articles 4 and 5 hereof,
                  nothing contained in this Indenture shall prevent any
                  consolidation or merger of the Company with or into the Parent
                  Guarantor, or shall prevent any sale or conveyance of the
                  property of the Company as an entirety or substantially as an
                  entirety to the Parent Guarantor."

                  (3) Section 11.07 of the Indenture is deleted in its entirety
together with any references thereto in the Indenture and replaced with
"[Intentionally Omitted]."

         Section 2.9. Conforming Changes. The provisions of the Indenture and
all Exhibits thereto shall be deemed revised to make all conforming changes as
well as changes to articles, verbs, verb tenses, singular and plural word forms,
syntax and other word forms or usage as may be necessary to accomplish the
intent of this Third Supplemental Indenture and as the context of such
provisions require.

                                  ARTICLE III
                                NOTATION OF NOTES

         Notes authenticated and delivered for transfer or exchange of
outstanding Notes after the Effective Time (as defined below), and all Notes
presented or delivered to the Trustee on after such date for the purpose of
being stamped, shall be stamped (unless textually revised as hereinafter
provided) by the Trustee with a notation substantially in the form as follows:

                           "THE INDENTURE DATED AS OF MARCH 31, 1998 REFERRED TO
                           IN THIS NOTE HAS BEEN AMENDED BY A FIRST SUPPLEMENTAL
                           INDENTURE DATED AS OF MARCH 31, 1998, A SECOND
                           SUPPLEMENTAL INDENTURE DATED AS OF DECEMBER 1, 1999,
                           AND A THIRD SUPPLEMENTAL INDENTURE DATED AS OF
                           FEBRUARY 14, 2000, PURSUANT TO WHICH CERTAIN
                           PROVISIONS OF THE INDENTURE HAVE BEEN AMENDED,
                           ELIMINATED OR OTHERWISE MODIFIED AS SET FORTH IN SUCH
                           FIRST, SECOND AND THIRD SUPPLEMENTAL INDENTURES.
                           COPIES OF THE FIRST, SECOND AND THIRD SUPPLEMENTAL
                           INDENTURES ARE ON FILE WITH, AND AVAILABLE ON REQUEST
                           FROM, THE TRUSTEE AND THE COMPANY."

                                  Page 8 of 11
<PAGE>   9

Any Notes hereafter authenticated or delivered may be textually revised, making
changes in phraseology and form (but not in substance) as may be appropriate so
as to conform, in the opinion of the Trustee and the Company, to modifications
made by this Third Supplemental Indenture.

                                   ARTICLE IV
                                  MISCELLANEOUS

         Section 4.1. Capitalized Terms. Capitalized terms used herein and not
otherwise defined have the meaning set forth in the Indenture.

         Section 4.2. Operation of Third Supplemental Indenture. This Third
Supplemental Indenture will become effective as of the date hereof.

         Section 4.3. Conflict with the Trust Indenture Act. If any provision of
this Third Supplemental Indenture modifies or excludes any provision of the
Trust Indenture Act that is required under such Act to be part of and govern
this Third Supplemental Indenture, the latter provision of the Trust Indenture
Act shall control. If any provision hereof modifies or excludes any provision of
the Trust Indenture Act that may be so modified or excluded, the latter
provision of the Trust Indenture Act shall be deemed to apply to this Third
Supplemental Indenture, as so modified or excluded, as the case may be.

         Section 4.4. Notes Deemed Conformed. As of the Effective Time, the
provisions of each Note then outstanding shall be deemed to be conformed,
without the necessity for any reissuance or exchange of such Note or any other
action on the part of the Holders, the Company, the Parent Guarantor or the
Trustee, so as to reflect this Third Supplemental Indenture.

         Section 4.5. Mutatis Mutandis. Except as specifically modified herein,
the Indenture and the Notes are in all respects ratified and confirmed (mutatis
mutandis) and shall remain in full force and effect in accordance with their
terms with all capitalized terms used herein without definition having the same
definition ascribed to them as in the Indenture. The Indenture shall be deemed
to have such other changes as to grammar, tense, syntax and like concepts as
shall be necessary to effect the changes contemplated herein.

         Section 4.6. No Additional Trustee Obligations. Except as otherwise
expressly provided herein, no duties, responsibilities or liabilities are
assumed, or shall be construed to be assumed, by the Trustee by reason of this
Third Supplemental Indenture. This Third Supplemental Indenture is executed and
accepted by the Trustee subject to all the terms and conditions set forth in the
Indenture with the same force and effect as if those terms and conditions were
repeated at length herein and made applicable to the Trustee with respect
hereto.

         Section 4.7. Successors. All agreements of the Company, the Parent
Guarantor and the Trustee in this Third Supplemental Indenture and in the
Indenture shall bind their respective successors.

         Section 4.8. Benefits of Third Supplemental Indenture. Nothing in this
Third Supplemental Indenture, express or implied, shall give to any person,
other than the parties hereto and their successors hereunder and the Holders,
any benefit or any legal or equitable right, remedy or claim under this Third
Supplemental Indenture or the Indenture.

         Section 4.9. Severability. In case any provision in this Third
Supplemental Indenture, or in the Indenture, shall be invalid, illegal or
unenforceable, the validity, legality and enforceability of the remaining
provisions shall not in any way be affected or impaired thereby, it being
intended that all of the provisions hereof shall be enforceable to the full
extent permitted by law.

                                  Page 9 of 11
<PAGE>   10

         Section 4.10. Headings. The Section headings of this Third Supplemental
Indenture have been inserted for convenience of reference only, are not to be
considered a part of this Third Supplemental Indenture and shall not modify or
restrict any of the terms or provisions hereof.

         Section 4.11. Multiple Originals. The parties may sign any number of
copies of this Third Supplemental Indenture. Each signed copy shall be an
original, but all of them together represent the same agreement.

         Section 4.12. The Trustee. The Trustee is not responsible in any manner
whatsoever for or in respect of the validity or sufficiency of this Third
Supplemental Indenture or for or in respect of the recitals contained herein,
all of which are made solely by the Company.

         Section 4.13. Governing Law. THE LAW OF THE STATE OF NEW YORK SHALL
GOVERN AND BE USED TO CONSTRUE AND ENFORCE THIS THIRD SUPPLEMENTAL INDENTURE.

                            [Signature Pages Follow]

         IN WITNESS WHEREOF, the parties hereto have caused this Third
Supplemental Indenture to be duly executed as of the date first above written.

                              COMPANY:
                              NABORS HOLDING COMPANY (formerly known as POOL
                              ENERGY SERVICES CO.)

                              By:  /s/ Daniel McLachlin
                                   ---------------------------------------------
                                   Name:  Daniel McLachlin
                                   Title: Secretary

                              GUARANTORS:
                              ASSOCIATED PETROLEUM SERVICES, INC.
                              INTERNATIONAL AIR DRILLING COMPANY
                              KUUKPIK - POOL ARCTIC ALASKA
                                   By:  Pool Alaska, Inc., d/b/a Pool Arctic
                                        Alaska
                              POOL ALASKA, INC.
                              POOL AMERICAS, INC.
                              POOL-AUSTRALIA, INC.
                              POOL COMPANY
                              POOL COMPANY TEXAS, LTD.
                                   By:  Pool Well Services Co., General Partner
                              POOL INTERNATIONAL, INC.
                              POOL WELL SERVICES CO.
                              PTX, INC.
                              SEA MAR, INC.
                              SEA MAR MANAGEMENT, INC.

                              By:  /s/ Daniel McLachlin
                                   ---------------------------------------------
                                   Name:  Daniel McLachlin
                                   Title: Secretary

                              PCNV, INC.

                              By:  /s/ Jay Weidenbach
                                   ---------------------------------------------
                                   Name:  Jay Weidenbach
                                   Title: Secretary

                                 Page 10 of 11
<PAGE>   11

                              PARENT GUARANTOR:
                              NABORS INDUSTRIES, INC.

                              By:  /s/ Anthony G. Petrello
                                   ---------------------------------------------
                                   Name:  Anthony G. Petrello
                                   Title: President and Chief Operating Officer

                              TRUSTEE:
                              HSBC BANK USA, as Trustee

                              By:  /s/ Frank J. Godino
                                   ---------------------------------------------
                                   Name:  Frank J. Godino
                                   Title: Vice President

                                 Page 11 of 11

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