<PAGE>   1
                                                                    EXHIBIT 10.2

                          REGISTRATION RIGHTS AGREEMENT


               This Registration Rights Agreement is made and entered into as of
May 18, 2000 (this "Agreement"), by and among GreyStone Digital Technology,
Inc., a Delaware corporation (the "Company"), and each of the Purchasers listed
on Schedule 1 attached hereto. Each of the Purchasers listed on Schedule 1
attached hereto is referred to herein as a "Purchaser" and are collectively
referred to herein as the "Purchasers."

               This Agreement is being entered into pursuant to the Series A
Convertible Preferred Stock Purchase Agreement, dated as of the date hereof, by
and among the Company and the Purchasers (the "Purchase Agreement").

               The Company and the Purchasers hereby agree as follows:

          1.   Definitions.

               Capitalized terms used and not otherwise defined herein shall
have the meanings given such terms in the Purchase Agreement. As used in this
Agreement, the following terms shall have the following meanings:

               "Advice" shall have the meaning set forth in Section 3(m).

               "Affiliate" means, with respect to any Person, any other Person
that directly or indirectly controls or is controlled by or under common control
with such Person. For the purposes of this definition, "control," when used with
respect to any Person, means the possession, direct or indirect, of the power to
direct or cause the direction of the management and policies of such Person,
whether through the ownership of voting securities, by contract or otherwise;
and the terms of "affiliated," "controlling" and "controlled" have meanings
correlative to the foregoing.

               "Blackout Period" shall have the meaning set forth in Section
3(n).

               "Board" shall have the meaning set forth in Section 3(n).

               "Business Day" means any day except Saturday, Sunday and any day
which shall be a legal holiday or a day on which banking institutions in the
state of New York generally are authorized or required by law or other
government actions to close.

               "Commission" means the Securities and Exchange Commission.

               "Common Stock" means the Company's Common Stock, par value $.001
per share.



<PAGE>   2
               "Effectiveness Date" means with respect to the Registration
Statement the earlier of the date which is (i) the 120th day following the
Filing Date and (ii) the date which is within five (5) days of the date on which
the Commission informs the Company that the Commission (i) will not review the
Registration Statement or (ii) that the Company may request the acceleration of
the effectiveness of the Registration Statement.

               "Effectiveness Period" shall have the meaning set forth in
Section 2(a).

               "Event" shall have the meaning set forth in Section 7(e).

               "Exchange Act" means the Securities Exchange Act of 1934, as
amended.

               "Filing Date" means within fifteen (15) Business Days after the
Company files its Form 10-K but in any event no later than July 21, 2000.

               "Holder" or "Holders" means the holder or holders, as the case
may be, from time to time of Registrable Securities, including, without
limitation, the Purchasers and their assigns.

               "Indemnified Party" shall have the meaning set forth in Section
5(c).

               "Indemnifying Party" shall have the meaning set forth in Section
5(c).

               "Liquidated Damages" shall have the meaning set forth in Section
7(e).

               "Losses" shall have the meaning set forth in Section 5(a).

               "OTC Bulletin Board" shall mean the over-the-counter electronic
bulletin board.

               "Person" means an individual or a corporation, partnership,
trust, incorporated or unincorporated association, joint venture, limited
liability company, joint stock company, government (or an agency or political
subdivision thereof) or other entity of any kind.

               "Preferred Stock" means the Series A Convertible Preferred Stock,
par value $0.001 per share and stated value $1,000 per share, of the Company
issued to the Purchasers pursuant to the Purchase Agreement.

               "Proceeding" means an action, claim, suit, investigation or
proceeding (including, without limitation, an investigation or partial
proceeding, such as a deposition), whether commenced or threatened.

               "Prospectus" means the prospectus included in the Registration
Statement (including, without limitation, a prospectus that includes any
information previously omitted from a prospectus filed as part of an effective
registration statement in reliance upon Rule 430A promulgated under the
Securities Act), as amended or supplemented by any prospectus



                                      -2-
<PAGE>   3
supplement, with respect to the terms of the offering of any portion of the
Registrable Securities covered by the Registration Statement, and all other
amendments and supplements to the Prospectus, including post-effective
amendments, and all material incorporated by reference in such Prospectus.

               "Registrable Securities" means: (i) the shares of Common Stock
issuable upon conversion of the Preferred Stock (the "Conversion Shares"), and
upon any stock split, stock dividend, recapitalization or similar event with
respect to such Conversion Shares or any Preferred Stock; (ii) the shares of
Common Stock issuable upon exercise of Warrants (the "Warrant Shares") issued
pursuant to the Purchase Agreement; and (iii) any other dividend or other
distribution with respect to, conversion or exchange of, or in replacement of,
Registrable Securities; provided, however, that Registrable Securities shall
include (but not be limited to) a number of shares of Common Stock equal to no
less than 150% of the maximum number of shares of Common Stock which would be
issuable upon conversion of the Preferred Stock and upon exercise of the
Warrants, assuming such conversion and exercise occurred on the Closing Date or
the Filing Date, whichever date would result in the greater number of
Registrable Securities. Notwithstanding anything herein contained to the
contrary, such registered shares of Common Stock shall be allocated among the
Holders pro rata based on the total number of Registrable Securities issued or
issuable as of each date that a Registration Statement, as amended, relating to
the resale of the Registrable Securities is declared effective by the
Commission. Notwithstanding anything contained herein to the contrary, if the
actual number of shares of Common Stock issuable upon conversion of the
Preferred Stock and upon exercise of the Warrants exceeds 150% of the number of
shares of Common Stock issuable upon conversion of the Preferred Stock and upon
exercise of the Warrants based upon a computation as at the Closing Date or the
Filing Date, the term "Registrable Securities" shall be deemed to include such
additional shares of Common Stock.

               "Registration Statement" means the registration statement and any
additional registration statements contemplated by Section 2, including (in each
case) the Prospectus, amendments and supplements to such registration statement
or Prospectus, including pre- and post-effective amendments, all exhibits
thereto, and all material incorporated by reference in such registration
statement.

               "Rule 144" means Rule 144 promulgated by the Commission pursuant
to the Securities Act, as such Rule may be amended from time to time, or any
similar rule or regulation hereafter adopted by the Commission having
substantially the same effect as such Rule.

               "Rule 158" means Rule 158 promulgated by the Commission pursuant
to the Securities Act, as such Rule may be amended from time to time, or any
similar rule or regulation hereafter adopted by the Commission having
substantially the same effect as such Rule.



                                      -3-
<PAGE>   4
               "Rule 415" means Rule 415 promulgated by the Commission pursuant
to the Securities Act, as such Rule may be amended from time to time, or any
similar rule or regulation hereafter adopted by the Commission having
substantially the same effect as such Rule.

               "Securities Act" means the Securities Act of 1933, as amended.

               "Special Counsel" means any special counsel to the Holders, for
which the Company will pay fees pursuant to Section 4.

               "Warrants" means the warrants to purchase shares of Common Stock
issued in connection with the Purchase Agreement, and any other warrants of like
tenor issued in substitution or exchange thereof.

          2.   Registration.

               On or prior to the Filing Date the Company shall prepare and file
with the Commission a "shelf" Registration Statement covering all Registrable
Securities for an offering to be made on a continuous basis pursuant to Rule
415, if applicable. The Registration Statement shall be on Form S-1 (or on
another appropriate form for such registration in accordance herewith). The
Company shall (i) not permit any securities other than the Registrable
Securities and those listed on Schedule 7(b) hereto to be included in the
Registration Statement and (ii) use its best efforts to cause the Registration
Statement to be declared effective as soon as possible after the filing thereof,
but in any event prior to the Effectiveness Date, and to keep such Registration
Statement continuously effective under the Securities Act until such date as is
the earlier of (x) the date when all Registrable Securities covered by such
Registration Statement have been sold or (y) the date on which the Registrable
Securities may be sold without any restriction pursuant to Rule 144(k) as
determined by the counsel to the Company pursuant to a written opinion letter,
addressed to the Company's transfer agent to such effect (the "Effectiveness
Period"). If an additional Registration Statement is required to be filed
because the actual number of shares of Common Stock into which the Preferred
Stock is convertible and the Warrants are exercisable exceeds the number of
shares of Common Stock initially registered in respect of the Conversion Shares
and the Warrant Shares based upon the initial computation of the number of
Registrable Shares required to be registered, the Company shall have 15 Business
Days to file such additional Registration Statement, and the Company shall use
its best efforts to cause such additional Registration Statement to be declared
effective by the Commission as soon as possible, but in no event later than 30
days after filing.

          3.   Registration Procedures.

               In connection with the Company's registration obligations
hereunder, the Company shall:



                                      -4-
<PAGE>   5
               (a) Prepare and file with the Commission on or prior to the
Filing Date, a Registration Statement on Form S-1 (or on another form
appropriate for such registration in accordance herewith) in accordance with the
method or methods of distribution thereof as specified by the Holders (except if
otherwise directed by the Holders), and cause the Registration Statement to
become effective and remain effective as provided herein; provided, however,
that not less than five (5) Business Days prior to the filing of the
Registration Statement or any related Prospectus or any amendment or supplement
thereto (including any document that would be incorporated therein by
reference), the Company shall (i) furnish to the Holders and any Special
Counsel, copies of all such documents proposed to be filed, which documents
(other than those incorporated by reference) will be subject to the review of
such Holders and such Special Counsel, and (ii) at the request of any Holder
cause its officers and directors, counsel and independent certified public
accountants to respond to such inquiries as shall be necessary, in the
reasonable opinion of counsel to such Holders, to conduct a reasonable
investigation within the meaning of the Securities Act. The Company shall not
file the Registration Statement or any such Prospectus or any amendments or
supplements thereto to which the Holders of a majority of the Registrable
Securities or any Special Counsel shall reasonably object in writing within
three (3) Business Days of their receipt thereof.

               (b) Prepare and file with the Commission such amendments,
including post-effective amendments, to the Registration Statement as may be
necessary to keep the Registration Statement continuously effective as to the
applicable Registrable Securities for the Effectiveness Period and prepare and
file with the Commission such additional Registration Statements in order to
register for resale under the Securities Act all of the Registrable Securities;
(ii) cause the related Prospectus to be amended or supplemented by any required
Prospectus supplement, and as so supplemented or amended to be filed pursuant to
Rule 424 (or any similar provisions then in force) promulgated under the
Securities Act; (iii) respond as promptly as possible to any comments received
from the Commission with respect to the Registration Statement or any amendment
thereto and as promptly as possible provide the Holders true and complete copies
of all correspondence from and to the Commission relating to the Registration
Statement; and (iv) comply in all material respects with the provisions of the
Securities Act and the Exchange Act with respect to the disposition of all
Registrable Securities covered by the Registration Statement during the
applicable period in accordance with the intended methods of disposition by the
Holders thereof set forth in the Registration Statement as so amended or in such
Prospectus as so supplemented.

               (c) Notify the Holders of Registrable Securities to be sold and
any Special Counsel as promptly as possible (and, in the case of (i)(A) below,
not less than five (5) Business Days prior to such filing) and (if requested by
any such Person) confirm such notice in writing no later than one (1) Business
Day following the day: (i)(A) when a Prospectus or any Prospectus supplement or
post-effective amendment to the Registration Statement is proposed to be filed;
(B) when the Commission notifies the Company whether there will be a "review" of
such Registration Statement and whenever the Commission comments in writing on
such



                                      -5-
<PAGE>   6
Registration Statement; and (C) with respect to the Registration Statement or
any post-effective amendment, when the same has become effective; (ii) of any
request by the Commission or any other Federal or state governmental authority
for amendments or supplements to the Registration Statement or Prospectus or for
additional information; (iii) of the issuance by the Commission of any stop
order suspending the effectiveness of the Registration Statement covering any or
all of the Registrable Securities or the initiation of any Proceedings for that
purpose; (iv) if at any time any of the representations and warranties of the
Company contained in any agreement contemplated hereby ceases to be true and
correct in all material respects; (v) of the receipt by the Company of any
notification with respect to the suspension of the qualification or exemption
from qualification of any of the Registrable Securities for sale in any
jurisdiction, or the initiation or threatening of any Proceeding for such
purpose; and (vi) of the occurrence of any event that makes any statement made
in the Registration Statement or Prospectus or any document incorporated or
deemed to be incorporated therein by reference untrue in any material respect or
that requires any revisions to the Registration Statement, Prospectus or other
documents so that, in the case of the Registration Statement or the Prospectus,
as the case may be, it will not contain any untrue statement of a material fact
or omit to state any 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.

               The Company shall promptly furnish to Special Counsel, without
charge, (i) any correspondence from the Commission or the Commission's staff to
the Company or its representatives relating to any Registration Statement and
(ii) promptly after the same is prepared and filed with the Commission, a copy
of any written response to the correspondence received from the Commission.

               (d) Use its best efforts to avoid the issuance of, or, if issued,
obtain the withdrawal of, (i) any order suspending the effectiveness of the
Registration Statement or (ii) any suspension of the qualification (or exemption
from qualification) of any of the Registrable Securities for sale in any
jurisdiction, at the earliest practicable moment.

               (e) If requested by the Holders of a majority in interest of the
Registrable Securities, (i) promptly incorporate in a Prospectus supplement or
post-effective amendment to the Registration Statement such information as the
Company reasonably agrees should be included therein and (ii) make all required
filings of such Prospectus supplement or such post-effective amendment as soon
as practicable after the Company has received notification of the matters to be
incorporated in such Prospectus supplement or post-effective amendment.

               (f) Furnish to each Holder and any Special Counsel, without
charge, at least one (1) conformed copy of each Registration Statement and each
amendment thereto, including financial statements and schedules, all documents
incorporated or deemed to be incorporated therein by reference, and all exhibits
to the extent requested by such Person (including those



                                      -6-
<PAGE>   7
previously furnished or incorporated by reference) promptly after the filing of
such documents with the Commission.

               (g) Promptly deliver to each Holder and any Special Counsel,
without charge, as many copies of the Registration Statement, Prospectus or
Prospectuses (including each form of prospectus) and each amendment or
supplement thereto as such Persons may reasonably request; and the Company
hereby consents to the use of such Prospectus and each amendment or supplement
thereto by each of the selling Holders in connection with the offering and sale
of the Registrable Securities covered by such Prospectus and any amendment or
supplement thereto.

               (h) Prior to any public offering of Registrable Securities, use
its best efforts to register or qualify or cooperate with the selling Holders
and any Special Counsel in connection with the registration or qualification (or
exemption from such registration or qualification) of such Registrable
Securities for offer and sale under the securities or Blue Sky laws of such
jurisdictions within the United States as any Holder requests in writing, to
keep each such registration or qualification (or exemption therefrom) effective
during the Effectiveness Period and to do any and all other acts or things
necessary or advisable to enable the disposition in such jurisdictions of the
Registrable Securities covered by a Registration Statement; provided, however,
that the Company shall not be required to qualify generally to do business in
any jurisdiction where it is not then so qualified or to take any action that
would subject it to general service of process in any such jurisdiction where it
is not then so subject or subject the Company to any material tax in any such
jurisdiction where it is not then so subject.

               (i) Cooperate with the Holders to facilitate the timely
preparation and delivery of certificates representing Registrable Securities to
be sold pursuant to a Registration Statement, which certificates shall be free
of all restrictive legends, and to enable such Registrable Securities to be in
such denominations and registered in such names as any Holder may request at
least two (2) Business Days prior to any sale of Registrable Securities.

               (j) Upon the occurrence of any event contemplated by Section
3(c)(vi), as promptly as possible, prepare a supplement or amendment, including
a post-effective amendment, to the Registration Statement or a supplement to the
related Prospectus or any document incorporated or deemed to be incorporated
therein by reference, and file any other required document so that, as
thereafter delivered, neither the Registration Statement nor such Prospectus
will 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,
in the light of the circumstances under which they were made, not misleading.

               (k) Use its best efforts to cause all Registrable Securities
relating to such Registration Statement to be listed on OTC Bulletin Board and
any other securities exchange, quotation system, market or over-the-counter
bulletin board, if any, on which similar securities issued by the Company are
then listed as and when required pursuant to the Purchase Agreement.



                                      -7-
<PAGE>   8
               (l) Comply in all material respects with all applicable rules and
regulations of the Commission and make generally available to its security
holders earning statements satisfying the provisions of Section 11(a) of the
Securities Act and Rule 158 not later than 45 days after the end of any 12-month
period (or 90 days after the end of any 12-month period if such period is a
fiscal year) commencing on the first day of the first fiscal quarter of the
Company after the effective date of the Registration Statement, which statement
shall conform to the requirements of Rule 158.

               (m) Require each selling Holder to furnish to the Company
information regarding such Holder and the distribution of such Registrable
Securities as is required by law to be disclosed in the Registration Statement,
and the Company may exclude from such registration the Registrable Securities of
any such Holder who fails to furnish such information within a reasonable time
prior to the filing of each Registration Statement, supplemented Prospectus
and/or amended Registration Statement.

               If the Registration Statement refers to any Holder by name or
otherwise as the holder of any securities of the Company, then such Holder shall
have the right to require (if such reference to such Holder by name or otherwise
is not required by the Securities Act or any similar federal statute then in
force) the deletion of the reference to such Holder in any amendment or
supplement to the Registration Statement filed or prepared subsequent to the
time that such reference ceases to be required.

               Each Holder covenants and agrees that (i) it will not sell any
Registrable Securities under the Registration Statement until it received copies
of the Prospectus as then amended or supplemented as contemplated in Section
3(g) and confirmation from the Company or the Commission that such Registration
Statement and any post-effective amendments thereto have become effective as
contemplated by Section 3(c) and (ii) it and its officers, directors or
Affiliates, if any, will comply with the prospectus delivery requirements of the
Securities Act as applicable to them in connection with sales of Registrable
Securities pursuant to the Registration Statement.

               Each Holder agrees by its acquisition of such Registrable
Securities that, upon receipt of a notice from the Company of the occurrence of
any event of the kind described in Section 3(c)(ii), 3(c)(iii), 3(c)(iv),
3(c)(v) or 3(c)(vi), such Holder will forthwith discontinue disposition of such
Registrable Securities under the Registration Statement until such Holder has
copies of the supplemented Prospectus and/or amended Registration Statement
contemplated by Section 3(j), or until it is advised in writing (the "Advice")
by the Company that the use of the applicable Prospectus may be resumed, and, in
either case, has copies of any additional or supplemental filings that are
incorporated or deemed to be incorporated by reference in such Prospectus or
Registration Statement.



                                      -8-
<PAGE>   9
               (n) If (i) there is material non-public information regarding the
Company which the Company's Board of Directors (the "Board") reasonably -----
determines not to be in the Company's best interest to disclose and which the
Company is not otherwise required to disclose, or (ii) there is a significant
business opportunity (including, but not limited to, the acquisition or
disposition of assets (other than in the ordinary course of business) or any
merger, consolidation, tender offer or other similar transaction) available to
the Company which the Board reasonably determines not to be in the Company's
best interest to disclose and which the Company would be required to disclose
under the Registration Statement, then the Company may suspend effectiveness of
a registration statement for a period not to exceed 20 consecutive days,
provided that the Company may not suspend its obligation under this Section 3(n)
for more than 45 days in the aggregate during any 12 month period (each, a
"Blackout Period"); provided, however, that no such suspension shall be
permitted for consecutive 20 day periods, arising out of the same set of facts,
circumstances or transactions.

               (o) Within two (2) business days after the Registration Statement
which includes the Registrable Securities is ordered effective by the
Commission, the Company shall deliver, and shall cause legal counsel for the
Company to deliver, to the transfer agent for such Registrable Securities (with
copies to the Holders whose Registrable Securities are included in such
Registration Statement) confirmation that the Registration Statement has been
declared effective by the Commission in the form attached hereto as Exhibit A.

          4.   Registration Expenses

               All fees and expenses incident to the performance of or
compliance with this Agreement by the Company shall be borne by the Company
whether or not the Registration Statement is filed or becomes effective and
whether or not any Registrable Securities are sold pursuant to the Registration
Statement. The fees and expenses referred to in the foregoing sentence shall
include, without limitation, the following: (i) all registration and filing fees
(including, without limitation, fees and expenses (A) with respect to filings
required to be made with the OTC Bulletin Board and each other securities
exchange or market on which Registrable Securities are required hereunder to be
listed, (B) with respect to filings required to be made with the Commission and
(C) in compliance with state securities or Blue Sky laws (including, without
limitation, fees and disbursements of counsel for the Holders in connection with
Blue Sky qualifications of the Registrable Securities and determination of the
eligibility of the Registrable Securities for investment under the laws of such
jurisdictions as the Holders of a majority of Registrable Securities may
designate)), (ii) printing expenses (including, without limitation, expenses of
printing certificates for Registrable Securities and of printing prospectuses if
the printing of prospectuses is requested by the holders of a majority of the
Registrable Securities included in the Registration Statement), (iii) messenger,
telephone and delivery expenses, (iv) fees and disbursements of counsel for the
Company and Special Counsel for the Holders, in the case of the Special Counsel,
to a maximum amount of $15,000, (v) Securities Act liability insurance, if the
Company so desires such insurance, and (vi) fees and expenses of all other



                                      -9-
<PAGE>   10
Persons retained by the Company in connection with the consummation of the
transactions contemplated by this Agreement, including, without limitation, the
Company's independent public accountants (including the expenses of any comfort
letters or costs associated with the delivery by independent public accountants
of a comfort letter or comfort letters). In addition, the Company shall be
responsible for all of its internal expenses incurred in connection with the
consummation of the transactions contemplated by this Agreement (including,
without limitation, all salaries and expenses of its officers and employees
performing legal or accounting duties), the expense of any annual audit, the
fees and expenses incurred in connection with the listing of the Registrable
Securities on any securities exchange as required hereunder.

          5.   Indemnification

               (a) Indemnification by the Company. The Company shall,
notwithstanding any termination of this Agreement, indemnify and hold harmless
each Holder, the officers, directors, agents, brokers (including brokers who
offer and sell Registrable Securities as principal as a result of a pledge or
any failure to perform under a margin call of Common Stock), investment advisors
and employees of each of them, each Person who controls any such Holder (within
the meaning of Section 15 of the Securities Act or Section 20 of the Exchange
Act) and the officers, directors, agents and employees of each such controlling
Person, and the respective successors, assigns, estate and personal
representatives of each of the foregoing, to the fullest extent permitted by
applicable law, from and against any and all claims, losses, damages,
liabilities, penalties, judgments, costs (including, without limitation, costs
of investigation) and expenses (including, without limitation, attorneys' fees
and expenses) (collectively, "Losses"), as incurred, arising out of or relating
to any untrue or alleged untrue statement of a material fact contained in the
Registration Statement, any Prospectus or any form of prospectus or in any
amendment or supplement thereto or in any preliminary prospectus, or arising out
of or relating to any omission or alleged omission of a material fact required
to be stated therein or necessary to make the statements therein (in the case of
any Prospectus or form of prospectus or supplement thereto, in the light of the
circumstances under which they were made) not misleading, except to the extent,
but only to the extent, that such untrue statements or omissions are based
solely upon information regarding such Holder furnished in writing to the
Company by such Holder expressly for use therein, which information was
reasonably relied on by the Company for use therein or to the extent that such
information relates to such Holder or such Holder's proposed method of
distribution of Registrable Securities and was reviewed and expressly approved
in writing by such Holder expressly for use in the Registration Statement, such
Prospectus or such form of Prospectus or in any amendment or supplement thereto.
The Company shall notify the Holders promptly of the institution, threat or
assertion of any Proceeding of which the Company is aware in connection with the
transactions contemplated by this Agreement. Such indemnity shall remain in full
force and effect regardless of any investigation made by or on behalf of an
Indemnified Party (as defined in Section 5(c) herein) and shall survive the
transfer of the Registrable Securities by the Holders.



                                      -10-
<PAGE>   11
               (b) Indemnification by Holders. Each Holder shall, severally and
not jointly, indemnify and hold harmless the Company, the directors, officers,
agents and employees, each Person who controls the Company (within the meaning
of Section 15 of the Securities Act and Section 20 of the Exchange Act), and the
directors, officers, agents or employees of such controlling Persons, and the
respective successors, assigns, estate and personal representatives of each of
the foregoing, to the fullest extent permitted by applicable law, from and
against all Losses, as incurred, arising solely out of or based solely upon any
untrue statement of a material fact contained in the Registration Statement, any
Prospectus, or any form of prospectus, or arising solely out of or based solely
upon any omission of a material fact required to be stated therein or necessary
to make the statements therein (in the case of any Prospectus or form of
prospectus or supplement thereto, in the light of the circumstances under which
they were made) not misleading, to the extent, but only to the extent, that such
untrue statement or omission is contained in or omitted from any information so
furnished in writing by such Holder to the Company specifically for inclusion in
the Registration Statement or such Prospectus and that such information was
reasonably relied upon by the Company for use in the Registration Statement,
such Prospectus or such form of prospectus or to the extent that such
information relates to such Holder or such Holder's proposed method of
distribution of Registrable Securities and was reviewed and expressly approved
in writing by such Holder expressly for use in the Registration Statement, such
Prospectus or such form of Prospectus Supplement. Notwithstanding anything to
the contrary contained herein, the Holder shall be liable under this Section
5(b) for only that amount as does not exceed the net proceeds to such Holder as
a result of the sale of Registrable Securities pursuant to such Registration
Statement.

               (c) Conduct of Indemnification Proceedings. If any Proceeding
shall be brought or asserted against any Person entitled to indemnity hereunder
(an "Indemnified Party"), such Indemnified Party promptly shall notify the
Person from whom indemnity is sought (the "Indemnifying Party) in writing, and
the Indemnifying Party shall assume the defense thereof, including the
employment of counsel reasonably satisfactory to the Indemnified Party and the
payment of all fees and expenses incurred in connection with defense thereof;
provided, that the failure of any Indemnified Party to give such notice shall
not relieve the Indemnifying Party of its obligations or liabilities pursuant to
this Agreement, except (and only) to the extent that it shall be finally
determined by a court of competent jurisdiction (which determination is not
subject to appeal or further review) that such failure shall have proximately
and materially adversely prejudiced the Indemnifying Party.

               An Indemnified Party shall have the right to employ separate
counsel in any such Proceeding and to participate in the defense thereof, but
the fees and expenses of such counsel shall be at the expense of such
Indemnified Party or Parties unless: (1) the Indemnifying Party has agreed in
writing to pay such fees and expenses; or (2) the Indemnifying Party shall have
failed promptly to assume the defense of such Proceeding and to employ counsel
reasonably satisfactory to such Indemnified Party in any such Proceeding; or (3)
the named parties to any such Proceeding (including any impleaded parties)
include both such Indemnified Party and the



                                      -11-
<PAGE>   12
Indemnifying Party, and such Indemnified Party shall have been advised by
counsel that a conflict of interest is likely to exist if the same counsel were
to represent such Indemnified Party and the Indemnifying Party (in which case,
if such Indemnified Party notifies the Indemnifying Party in writing that it
elects to employ separate counsel at the expense of the Indemnifying Party, the
Indemnifying Party shall not have the right to assume the defense thereof and
such counsel shall be at the expense of the Indemnifying Party). The
Indemnifying Party shall not be liable for any settlement of any such Proceeding
effected without its written consent, which consent shall not be unreasonably
withheld. No Indemnifying Party shall, without the prior written consent of the
Indemnified Party, effect any settlement of any pending Proceeding in respect of
which any Indemnified Party is a party, unless such settlement includes an
unconditional release of such Indemnified Party from all liability on claims
that are the subject matter of such Proceeding.

               All fees and expenses of the Indemnified Party (including
reasonable fees and expenses to the extent incurred in connection with
investigating or preparing to defend such Proceeding in a manner not
inconsistent with this Section) shall be paid to the Indemnified Party, as
incurred, within 10 Business Days of written notice thereof to the Indemnifying
Party (regardless of whether it is ultimately determined that an Indemnified
Party is not entitled to indemnification hereunder; provided, that the
Indemnifying Party may require such Indemnified Party to undertake to reimburse
all such fees and expenses to the extent it is finally judicially determined
that such Indemnified Party is not entitled to indemnification hereunder).

               (d) Contribution. If a claim for indemnification under Section
5(a) or 5(b) is unavailable to an Indemnified Party because of a failure or
refusal of a governmental authority to enforce such indemnification in
accordance with its terms (by reason of public policy or otherwise), then each
Indemnifying Party, in lieu of indemnifying such Indemnified Party, shall
contribute to the amount paid or payable by such Indemnified Party as a result
of such Losses, in such proportion as is appropriate to reflect the relative
fault of the Indemnifying Party and Indemnified Party in connection with the
actions, statements or omissions that resulted in such Losses 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 any action in question, including any untrue or alleged untrue
statement of a material fact or omission or alleged omission of a material fact,
has been taken or made by, or relates to information supplied by, such
Indemnifying, Party or Indemnified Party, and the parties' relative intent,
knowledge, access to information and opportunity to correct or prevent such
action, statement or omission. The amount paid or payable by a party as a result
of any Losses shall be deemed to include, subject to the limitations set forth
in Section 5(c), any reasonable attorneys' or other reasonable fees or expenses
incurred by such party in connection with any Proceeding to the extent such
party would have been indemnified for such fees or expenses if the
indemnification provided for in this Section was available to such party in
accordance with its terms. Notwithstanding anything to the contrary contained
herein, the Holder shall be liable or required to contribute under this Section
5(c) for only that amount as



                                      -12-
<PAGE>   13
does not exceed the net proceeds to such Holder as a result of the sale of
Registrable Securities pursuant to such Registration Statement.

               The parties hereto agree that it would not be just and equitable
if contribution pursuant to this Section 5(d) were determined by pro rata
allocation or by any other method of allocation that does not take into account
the equitable considerations referred to in the immediately preceding paragraph.
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 indemnity and contribution agreements contained in this
Section are in addition to any liability that the Indemnifying Parties may have
to the Indemnified Parties

          6.   Rule 144.

               As long as any Holder owns Preferred Shares, Conversion Shares,
Warrants or Warrant Shares, the Company covenants to timely file (or obtain
extensions in respect thereof and file within the applicable grace period) all
reports required to be filed by the Company after the date hereof pursuant to
Section 13(a) or 15(d) of the Exchange Act and, if any Holder so requests or if
such reports have not been filed by the Company with the Commission pursuant to
the Commission's "electronic data gathering and retrieval" (EDGAR) service, to
promptly furnish the Holders with true and complete copies of all such filings.
As long as any Holder owns Preferred Shares, Conversion Shares, Warrants or
Warrant Shares, if the Company is not required to file reports pursuant to
Section 13(a) or 15(d) of the Exchange Act, it will prepare and furnish to the
Holders and make publicly available in accordance with Rule 144(c) promulgated
under the Securities Act annual and quarterly financial statements, together
with a discussion and analysis of such financial statements in form and
substance substantially similar to those that would otherwise be required to be
included in reports required by Section 13(a) or 15(d) of the Exchange Act, as
well as any other information required thereby, in the time period that such
filings would have been required to have been made under the Exchange Act. The
Company further covenants that it will take such further action as any Holder
may reasonably request, all to the extent required from time to time to enable
such Person to sell Conversion Shares and Warrant Shares without registration
under the Securities Act within the limitation of the exemptions provided by
Rule 144 promulgated under the Securities Act, including providing any legal
opinions of counsel to the Company referred to in the Purchase Agreement. Upon
the request of any Holder, the Company shall deliver to such Holder a written
certification of a duly authorized officer as to whether it has complied with
such requirements.

          7.   Miscellaneous.

               (a) Remedies. In the event of a breach by the Company or by a
Holder, of any of their obligations under this Agreement, each Holder or the
Company, as the case may be, in addition to being entitled to exercise all
rights granted by law and under this Agreement,



                                      -13-
<PAGE>   14
including recovery of damages, will be entitled to specific performance of its
rights under this Agreement. The Company and each Holder agree that monetary
damages would not provide adequate compensation for any losses incurred by
reason of a breach by it of any of the provisions of this Agreement and hereby
further agrees that, in the event of any action for specific performance in
respect of such breach, it shall waive the defense that a remedy at law would be
adequate.

               (b) No Inconsistent Agreements. Neither the Company nor any of
its subsidiaries has, as of the date hereof entered into and currently in
effect, nor shall the Company or any of its subsidiaries, on or after the date
of this Agreement, enter into any agreement with respect to its securities that
is inconsistent with the rights granted to the Holders in this Agreement or
otherwise conflicts with the provisions hereof. Neither the Company nor any of
its subsidiaries has previously entered into any agreement currently in effect
granting any registration rights with respect to any of its securities to any
Person, except as set forth on Schedule 7(b) hereto. Without limiting the
generality of the foregoing, without the written consent of the Holders of a
majority of the then outstanding Registrable Securities, the Company shall not
grant to any Person the right to request the Company to register any securities
of the Company under the Securities Act unless the rights so granted are subject
in all respects to the prior rights in full of the Holders set forth herein, and
are not otherwise in conflict with the provisions of this Agreement.

               (c) No Piggyback on Registrations. Neither the Company nor any of
its security holders (other than the Holders in such capacity pursuant hereto
and those listed on Schedule 7(b) hereto) may include securities of the Company
in the Registration Statement, and the Company shall not after the date hereof
enter into any agreement providing such right to any of its security holders,
unless the right so granted is subject in all respects to the prior rights in
full of the Holders set forth herein, and is not otherwise in conflict with the
provisions of this Agreement.

               (d) Piggy-Back Registrations. If at any time when there is not an
effective Registration Statement covering (i) Conversion Shares or (ii) Warrant
Shares, the Company shall determine to prepare and file with the Commission a
registration statement relating to an offering for its own account or the
account of others under the Securities Act of any of its equity securities,
other than on Form S-4 or Form S-8 (each as promulgated under the Securities
Act) or its then equivalents relating to equity securities to be issued solely
in connection with any acquisition of any entity or business or equity
securities issuable in connection with stock option or other employee benefit
plans, the Company shall send to each holder of Registrable Securities written
notice of such determination and, if within 30 days after receipt of such
notice, any such holder shall so request in writing (which request shall specify
the Registrable Securities intended to be disposed of by the Holders), the
Company will cause the registration under the Securities Act of all Registrable
Securities which the Company has been so requested to register by the holder, to
the extent requisite to permit the disposition of the Registrable Securities so
to be



                                      -14-
<PAGE>   15
registered, provided that if at any time after giving written notice of its
intention to register any securities 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 or to delay registration of such
securities, the Company may, at its election, give written notice of such
determination to such holder and, thereupon, (i) in the case of a determination
not to register, shall be relieved of its obligation to register any Registrable
Securities in connection with such registration (but not from its obligation to
pay expenses in accordance with Section 4 hereof), and (ii) in the case of a
determination to delay registering, shall be permitted to delay registering any
Registrable Securities being registered pursuant to this Section 7(d) for the
same period as the delay in registering such other securities. The Company shall
include in such registration statement all or any part of such Registrable
Securities such holder requests to be registered; provided, however, that the
Company shall not be required to register any Registrable Securities pursuant to
this Section 7(d) that are eligible for sale pursuant to Rule 144(k) of the
Securities Act. In the case of an underwritten public offering, if the managing
underwriter(s) should reasonably object to the inclusion of the Registrable
Securities in such registration statement, then if the Company after
consultation with the managing underwriter should reasonably determine that the
inclusion of such Registrable Securities would materially adversely affect the
offering contemplated in such registration statement, and, based on such
determination, recommends inclusion in such registration statement of fewer or
none of the Registrable Securities of the Holders, then, as applicable (x) the
number of Registrable Securities of the Holders included in such registration
statement shall be reduced pro-rata among such Holders (based upon the number of
Registrable Securities requested to be included in the registration), or (y)
none of the Registrable Securities of the Holders shall be included in such
registration statement; provided, however, that if securities are being offered
for the account of other persons or entities as well as the Company, such
reduction of the number of Registrable Securities intended to be offered by the
Holders shall not represent a greater fraction than the fraction of similar
reductions imposed on such other persons or entities (other than the Company).

               (e) Failure to File Registration Statement and Other Events. The
Company and the Purchasers agree that the Holders will suffer damages if the
Registration Statement is not filed on or prior to the Filing Date and not
declared effective by the Commission on or prior to the Effectiveness Date and
maintained in the manner contemplated herein during the Effectiveness Period or
if certain other events occur. The Company and the Holders further agree that it
would not be feasible to ascertain the extent of such damages with precision.
Accordingly, if (i) the Registration Statement is not filed on or prior to the
Filing Date, or is not declared effective by the Commission on or prior to the
Effectiveness Date (or in the event an additional Registration Statement is
filed because the actual number of shares of Common Stock into which the
Preferred Stock is convertible and the Warrants are exercisable exceeds the
number of shares of Common Stock initially registered is not filed and declared
effective within the time periods set forth in Section 2 herein), or (ii) the
Company fails to file with the Commission a request for acceleration in
accordance with Rule 461 promulgated under the Securities Act within five (5)
Business Days of the date that the Company is notified (orally or in



                                      -15-
<PAGE>   16
writing, whichever is earlier) by the Commission that a Registration Statement
will not be "reviewed," or not subject to further review, or (iii) the
Registration Statement is filed with and declared effective by the Commission
but thereafter ceases to be effective as to all Registrable Securities at any
time prior to the expiration of the Effectiveness Period, without being
succeeded immediately by a subsequent Registration Statement filed with and
declared effective by the Commission, or (iv) trading in the Common Stock shall
be suspended or if the Common Stock is delisted from OTC Bulletin Board for any
reason for more than five (5) Business Days in the aggregate, or (v) the
conversion or exercise rights of the Holders are suspended for any reason,
including by the Company, or (vi) the Company breaches in a material respect any
covenant or other material term or condition to this Agreement, the Certificate
of Designation, the Purchase Agreement (other than a representation or warranty
contained therein) or any other agreement, document, certificate or other
instrument delivered in connection with the transactions contemplated hereby and
thereby, and such breach continues for a period of thirty days after written
notice thereof to the Company, or (vii) the Company has breached Section 3(n) of
this Agreement (any such failure or breach being referred to as an "Event"), the
Company shall pay as liquidated damages for such failure and not as a penalty
(the "Liquidated Damages") to each Holder an amount equal to 1% of such Holder's
pro rata share of the purchase price paid by all Holders for all shares of
Preferred Stock purchased and then outstanding pursuant to the Purchase
Agreement for the initial 30 day period following the Event until the applicable
Event has been cured, which amount shall be pro rated for any period less than
30 days, and 2% of such Holder's pro rata share of the purchase price paid by
all Holders for all shares of Preferred Stock purchased and then outstanding
pursuant to the Purchase Agreement for each thirty 30 day period thereafter
until the applicable Event has been cured, which shall be pro rated for any
period less than 30 days (the "Periodic Amount"); provided, however, that if the
Company has responded to any and each of the Commission's comments with regard
to the filing of the Registration Statement within 15 days of the Company's
receipt of each of the Commission's comments, the Periodic Amount accruing
pursuant to Section 7(e)(i) for failure of the Registration Statement to be
declared effective by the Effectiveness Date shall be equal to 1% for each 30
day period until the Registration Statement is declared effective, which amount
shall be pro rated for any period less than 30 days. Payments to be made
pursuant to this Section 7(e) shall be due and payable immediately upon demand
in shares of Common Stock based on the closing bid price of the Common Stock on
the date of payment of such Periodic Amount, which shares of Common Stock shall
be registered under the Securities Act pursuant to either the Registration
Statement (if payment of the Periodic Amount is made prior to the effectiveness
of the Registration Statement) or any other registration statement to be filed
by the Company relating to an offering for its own account or the account of
others. The parties agree that the Periodic Amount represents a reasonable
estimate on the part of the parties, as of the date of this Agreement, of the
amount of damages that may be incurred by the Holders if the Registration
Statement is not filed on or prior to the Filing Date or has not been declared
effective by the Commission on or prior to the Effectiveness Date and maintained
in the manner contemplated herein during the Effectiveness Period or if any
other Event as described herein has occurred.



                                      -16-
<PAGE>   17
          (f)  Specific Enforcement, Consent to Jurisdiction.

               (i) The Company and the Holders acknowledge and agree that
irreparable damage would occur in the event that any of the provisions of this
Registration Rights Agreement or the Purchase Agreement were not performed in
accordance with their specific terms or were otherwise breached. It is
accordingly agreed that the parties shall be entitled to an injunction or
injunctions to prevent or cure breaches of the provisions of this Registration
Rights Agreement or the Purchase Agreement and to enforce specifically the terms
and provisions hereof or thereof, this being in addition to any other remedy to
which any of them may be entitled by law or equity.

               (ii) Each of the Company and the Purchasers (i) hereby
irrevocably submits to the jurisdiction of the United States District Court for
the Southern District of New York and the courts of the State of New York
located in New York county for the purposes of any suit, action or proceeding
arising out of or relating to this Agreement or the Purchase Agreement and (ii)
hereby waives, and agrees not to assert in any such suit, action or proceeding,
any claim that it is not personally subject to the jurisdiction of such court,
that the suit, action or proceeding is brought in an inconvenient forum or that
the venue of the suit, action or proceeding is improper. Each of the Company and
the Purchasers consents to process being served in any such suit, action or
proceeding by mailing a copy thereof to such party at the address in effect for
notices to it under this Agreement and agrees that such service shall constitute
good and sufficient service of process and notice thereof. Nothing in this
Section 7(f) shall affect or limit any right to serve process in any other
manner permitted by law.

               (g) Amendments and Waivers. The provisions of this Agreement,
including the provisions of this sentence, may not be amended, modified or
supplemented, and waivers or consents to departures from the provisions hereof
may not be given, unless the same shall be in writing and signed by the Company
and each of the Holders. Notwithstanding the foregoing, a waiver or consent to
depart from the provisions hereof with respect to a matter that relates
exclusively to the rights of Holders and that does not directly or indirectly
affect the rights of other Holders may be given by Holders of at least a
majority of the Registrable Securities to which such waiver or consent relates;
provided, however, that the provisions of this sentence may not be amended,
modified, or supplemented except in accordance with the provisions of the
immediately preceding sentence.

               (h) Notices. Any and all notices or other communications or
deliveries required or permitted to be provided hereunder shall be in writing
and shall be deemed given and effective on the earlier of (i) the date of
transmission, if such notice or communication is delivered via facsimile at the
facsimile telephone number specified for notice prior to 5:00 p.m., pacific
time, on a Business Day, (ii) the Business Day after the date of transmission,
if such notice or communication is delivered via facsimile at the facsimile
telephone number specified for notice later than 5:00 p.m., pacific time, on any
date and earlier than 11:59 p.m., pacific time,



                                      -17-
<PAGE>   18
on such date, (iii) the Business Day following the date of mailing, if sent by
nationally recognized overnight courier service or (iv) actual receipt by the
party to whom such notice is required to be given. The addresses for such
communications shall be with respect to each Holder at its address set forth
under its name on Schedule 1 attached hereto, or with respect to the Company,
addressed to:

        GreyStone Digital Technology, Inc.
        4950 Murphy Canyon Road
        San Diego, CA 92123
        Attention: Carolyn Harris, Esq.
        Facsimile no.: (858) 874-7019

or to such other address or addresses or facsimile number or numbers as any such
party may most recently have designated in writing to the other parties hereto
by such notice. Copies of notices to any Holder shall be sent to the addresses
listed on Schedule 1 attached hereto, if applicable. Copies of notices to the
Company shall be sent to Resch Polster Alpert & Berger LLP, 10390 Santa Monica
Boulevard, 4th Floor, Los Angeles, California 90025, Attention: Aaron A.
Grunfeld, Esq., Facsimile no.: (310) 552-3209. Copies of notices to the Holders
shall be sent to (i) Parker Chapin LLP, The Chrysler Building, 405 Lexington
Avenue, New York, New York 10174, Attention: Christopher S. Auguste, Esq.,
Facsimile no.: (212) 704-6288.

               (i) Successors and Assigns. This Agreement shall be binding upon
and inure to the benefit of the parties and their successors and permitted
assigns and shall inure to the benefit of each Holder and its successors and
assigns. The Company may not assign this Agreement or any of its rights or
obligations hereunder without the prior written consent of each Holder. Each
Holder may assign its rights hereunder in the manner and to the Persons as
permitted under the Purchase Agreement.

               (j) Assignment of Registration Rights. The rights of each Holder
hereunder, including the right to have the Company register for resale
Registrable Securities in accordance with the terms of this Agreement, shall be
automatically assignable by each Holder to any transferee of such Holder of all
or a portion of the Warrants or shares of Preferred Stock or the Registrable
Securities if: (i) the Holder 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 reasonable time after such assignment, (ii) the Company is, within a
reasonable time after such transfer or assignment, furnished with written notice
of (a) the name and address of such transferee or assignee, and (b) the
securities with respect to which such registration rights are being transferred
or assigned, (iii) following such transfer or assignment the further disposition
of such securities by the transferee or assignees is restricted under the
Securities Act and applicable state securities laws, (iv) at or before the time
the Company receives the written notice contemplated by clause (ii) of this
Section, the transferee or assignee agrees in writing with the Company to be
bound by all of the provisions of this Agreement, and (v) such transfer shall
have been made in



                                      -18-
<PAGE>   19
accordance with the applicable requirements of the Purchase Agreement. In
addition, each Holder shall have the right to assign its rights hereunder to any
other Person with the prior written consent of the Company, which consent shall
not be unreasonably withheld. The rights to assignment shall apply to the
Holders (and to subsequent) successors and assigns.

               (k) Counterparts. This Agreement may be executed in any number of
counterparts, each of which when so executed shall be deemed to be an original
and, all of which taken together shall constitute one and the same Agreement. In
the event that any signature is delivered by facsimile transmission, such
signature shall create a valid binding obligation of the party executing (or on
whose behalf such signature is executed) the same with the same force and effect
as if such facsimile signature were the original thereof.

               (l) Governing Law. This Agreement shall be governed by and
construed in accordance with the laws of the State of New York, without regard
to principles of conflicts of law thereof. This Agreement shall not be
interpreted or construed with any presumption against the party causing this
Agreement to be drafted.

               (m) Cumulative Remedies. The remedies provided herein are
cumulative and not exclusive of any remedies provided by law.

               (n) Severability. If any term, provision, covenant or restriction
of this Agreement is held to be invalid, illegal, void or unenforceable in any
respect, 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
reasonable 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.

               (o) Headings. The headings herein are for convenience only, do
not constitute a part of this Agreement and shall not be deemed to limit or
affect any of the provisions hereof.

               (p) Shares Held by the Company and its Affiliates. Whenever the
consent or approval of Holders of a specified percentage of Registrable
Securities is required hereunder, Registrable Securities held by the Company or
its Affiliates (other than any Holder or transferees or successors or assigns
thereof if such Holder is deemed to be an Affiliate solely by reason of its
holdings of such Registrable Securities) shall not be counted in determining
whether such consent or approval was given by the Holders of such required
percentage and shall not be counted as outstanding.



                                      -19-
<PAGE>   20
[REMAINDER OF PAGE INTENTIONALLY LEFT BLANK]



                                      -20-
<PAGE>   21
               IN WITNESS WHEREOF, the parties hereto have caused this
Registration Rights Agreement to be duly executed by their respective authorized
persons as of the date first indicated above.



                                    GREYSTONE DIGITAL TECHNOLOGY, INC.



                                    By: /s/
                                       -----------------------------------------
                                       Name:
                                       Title:


                                    THE KESHET FUND L.P.



                                    By: /s/
                                       -----------------------------------------
                                       Name:
                                       Title:


                                    KESHET L.P.



                                    By: /s/
                                       -----------------------------------------
                                       Name:
                                       Title:


                                    TALBIYA B. INVESTMENTS LIMITED



                                    By: /s/
                                       -----------------------------------------
                                       Name:
                                       Title:



<PAGE>   22




                                 NESHER LIMITED



                                    By: /s/
                                       -----------------------------------------
                                       Name:
                                       Title:


                                    ESQUIRE TRADE & FINANCE INC.



                                    By: /s/
                                       -----------------------------------------
                                       Name:
                                       Title:


                                    CELESTE TRUST REG.



                                    By: /s/
                                       -----------------------------------------
                                       Name:
                                       Title:


                                    THE ENDEAVOUR CAPITAL FUND S.A.



                                    By: /s/
                                       -----------------------------------------
                                       Name:
                                       Title:


                                    THE GROSS FOUNDATION



                                    By: /s/
                                       -----------------------------------------
                                       Name:
                                       Title:




<PAGE>   23
                                    THE HEWLETT FUND



                                    By: /s/
                                       -----------------------------------------
                                       Name:
                                       Title:


                                    WEST CAPITAL & ASSOCIATES INC.



                                    By: /s/
                                       -----------------------------------------
                                       Name:
                                       Title:


                                    BURNS PARTICIPATION CORP.



                                    By: /s/
                                       -----------------------------------------
                                       Name:
                                       Title:


                                     AMRO INTERNATIONAL, S.A.



                                    By: /s/
                                       -----------------------------------------
                                       Name:
                                       Title:


                                    CANDID INVESTMENTS LTD.



                                    By: /s/
                                       -----------------------------------------
                                       Name: INTERNATIONAL FIRST SECRETARIAL
                                             GROUP LTD
                                       Title:   SECRETARY



<PAGE>   24
                                                                       EXHIBIT A

                         FORM OF NOTICE OF EFFECTIVENESS
                            OF REGISTRATION STATEMENT


[TRANSFER AGENT]
[ADDRESS]
Attn:  _____________

                  Re: GreyStone Digital Technology, Inc.

Ladies and Gentlemen:

               We are counsel to GreyStone Digital Technology, Inc., a Delaware
corporation (the "COMPANY"), and have represented the Company in connection with
that certain Series A Convertible Preferred Stock Purchase Agreement (the
"PURCHASE AGREEMENT"), dated as of May 18, 2000, by and among the Company and
the purchasers named therein (collectively, the "Holders") pursuant to which the
Company issued to the Holders shares of its Series A Convertible Preferred
Stock, par value $0.001 per share (the "PREFERRED SHARES"), and issued warrants
(the "WARRANTS") to purchase shares of the Company's common stock, par value
$.001 per share (the "COMMON STOCK"), to the placement advisor in connection
with such sale and issuance of Preferred Shares. Pursuant to the Purchase
Agreement, the Company has also entered into a Registration Rights Agreement
with the Holders (the "REGISTRATION RIGHTS AGREEMENT"), dated as of May 18,
2000, pursuant to which the Company agreed, among other things, to register the
Registrable Securities (as defined in the Registration Rights Agreement),
including the shares of Common Stock issuable upon conversion of the Preferred
Shares and exercise of the Warrants, under the Securities Act of 1933, as
amended (the "1933 ACT"). In connection with the Company's obligations under the
Registration Rights Agreement, on ________________, 2000, the Company filed a
Registration Statement on Form ___ (File No. 333-________) (the "REGISTRATION
STATEMENT") with the Securities and Exchange Commission (the "SEC") relating to
the resale of the Registrable Securities which names each of the present Holders
as a selling stockholder thereunder.

               In connection with the foregoing, we advise you that a member of
the SEC's staff has advised us by telephone that the SEC has entered an order
declaring the Registration Statement effective under the 1933 Act at [ENTER TIME
OF EFFECTIVENESS] on [ENTER DATE OF EFFECTIVENESS] and we have no knowledge,
after telephonic inquiry of a member of the SEC's staff, that any stop order
suspending its effectiveness has been issued or that any proceedings for that
purpose are pending before, or threatened by, the SEC and, accordingly, the
Registrable Securities are available for resale under the 1933 Act in the manner
specified in, and pursuant to the terms of the Registration Statement.

                                                   Very truly yours,




                                                   By:

cc:            [LIST NAMES OF HOLDERS]