<PAGE>
 
                                                                   EXHIBIT 10.49
                               WARRANT AGREEMENT
                        (GUARANTEE OF SWITCH FINANCING)

     This WARRANT AGREEMENT, dated as of March 5, 1998, between EQUALNET HOLDING
CORP., a Texas corporation (the "Company"), and MICHAEL T. WILLIS, a resident of
Harris County, Texas ("Willis" and, together with any transferee of
Warrants or Warrant Shares, the "Warrant Holders(s)").

     WHEREAS, Willis Group, LLC ("WG"), the Company, EqualNet Corporation,
Telesource, Inc., and EqualNet Wholesale Services, Inc., have entered into a
certain Note and Warrant Purchase Agreement (the "Note Purchase Agreement")
dated October 1, 1997, and WG, the Company and EQ Acquisition Sub, Inc., a
Delaware corporation ("Sub") have entered into a certain Switch Agreement (the
"Switch Agreement") dated December 2, 1997; and

     WHEREAS, the Company proposes to issue to Willis as consideration 
for Willis's guarantee of certain financing obtained by Sub common stock 
purchase warrants (the "Warrants") to purchase up to 500,000 shares (the 
"Warrant Shares") of the Company's common stock, par value $0.01 per share (the 
"Common Stock"), each Warrant entitling the holder thereof to purchase one share
of Common Stock.

     NOW, THEREFORE, in consideration of the premises and the mutual agreements 
herein and in the Agreement set forth and for other good and valuable 
consideration, the parties hereto agree as follows:

     1.   ISSUANCE OF WARRANTS: FORM OF WARRANT.  As of the date hereof the 
Company will issue and deliver the Warrants to Willis.  The aggregate number of 
Warrants to be issued and delivered shall be 500,000 (subject to any further 
limitation provided herein).  The Warrants shall be exercisable on or after the 
date hereof.  The text of each Warrant shall be substantially as set forth in 
the Warrant Certificate attached as Exhibit A hereto.  The Warrants shall be 
executed on behalf of the Company by the manual or facsimile signature of the 
present or any future Chairman of the Board, President, or Vice President of the
Company, attested by the manual or facsimile signature of the present or future 
Secretary or an Assistant Secretary of the Company.  A Warrant bearing the 
manual or facsimile signature of individuals who were at any time the proper 
officers of the Company shall bind the Company notwithstanding that such 
individuals or any of them shall have ceased to hold such offices prior to the 
delivery of such Warrant or did not hold such offices on the date of this 
Warrant Agreement.

     Warrants shall be dated as of the date of execution thereof by the Company 
either upon initial issuance or upon division, exchange, substitution or 
transfer.

     The demand and the piggy-back registration rights set forth in Section 16 
hereof may be exercised at any time during the term of the Warrants.

<PAGE>

     2.   REPRESENTATIONS AND WARRANTIES.

     (a)  The Company hereby represents and warrants as follows:

          (i) POWER AND AUTHORITY. The Company has all requisite corporate power
     and authority, and has taken all corporate action necessary, to execute,
     deliver and perform this Warrant Agreement, to grant, issue, and deliver
     the Warrants and to authorize and reserve for issuance and, upon payment
     from time to time of the Exercise Price, to issue and deliver the shares of
     Common Stock or other securities issuable upon exercise of the Warrants.
     This Warrant Agreement has been duly executed and delivered by the Company.

         (ii) RESERVATION, ISSUANCE AND DELIVERY OF COMMON STOCK. There have
     been reserved for issuance, and the Company shall at all times keep
     reserved, out of the authorized and unissued shares of Common Stock, a
     number of shares sufficient to provide for the exercise of the rights of
     purchase represented by the Warrants, and such shares, when issued upon
     receipt of payment therefor or upon a net exercise in accordance with the
     terms of the Warrants and of this Warrant Agreement, will be legally and
     validly issued, fully paid and non-assessable and will be free of any
     preemptive rights of shareholders or any restrictions.

     (b)  The Warrant Holder hereby represents and warrants as follows:

          (i) ACCREDITED INVESTOR. The Warrant Holder is an "accredited
investor" within the meaning of Rule 501 under Regulation D promulgated under
the Securities Act, is experienced in evaluating investments in companies such
as the Company, has such knowledge and experience in financial and business
matters as to be capable of evaluating the merits and risks of its investment
and has the ability to bear the entire economic risk of its investment. The
Warrant Holder has made its own evaluation of its investment in the
Warrants, based upon such information as is available to it and without reliance
upon the Company or any other person or entity, and the Warrant Holder agrees
that neither the Company nor any other person or entity has any obligation to
furnish any additional information to the Warrant Holder except as expressly set
forth herein.

     3. CONDITIONS TO PURCHASE. Willis's obligations hereunder shall be subject
to satisfaction of the following conditions on or before the date hereof:

          (a) All corporate proceedings and other legal matters incident to the
     authorization, form and validity of this Warrant Agreement and the Warrants
     and all other legal matters relating to this Warrant Agreement, the
     Warrants and the transactions contemplated hereby shall be satisfactory in
     all respects to Vinson & Elkins L.L.P., counsel for Willis, in their
     reasonable judgment, and the Company shall have furnished to such counsel
     all documents and information that they may reasonably request to enable
     them to pass judgment upon such matters.

          (b) There shall have been duly tendered to Willis or upon the order of
     Willis a certificate or certificates representing the Warrants.

                                     -2- 
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     4.   REGISTRATION.  The Warrants shall be numbered and shall be registered 
on the books of the Company (the "Warrant Register") as they are issued.  The 
Warrants shall be registered initially in such names and such denominations as 
Willis has specified to the Company.

     5.  EXCHANGE OF WARRANT CERTIFICATES. Subject to any restriction upon
transfer set forth in this Warrant Agreement, each Warrant certificate may be
exchanged at the option of the Warrant Holder thereof for another certificate or
certificates of different denominations entitling the Warrant Holder thereof
to purchase upon surrender to the Company or its duly authorized agent a like
aggregate number of Warrant Shares as the certificate or certificates
surrendered then entitle such Warrant Holder to purchase. Any Warrant Holder
desiring to exchange a Warrant certificate or certificates shall make such
request in writing delivered to the Company, and shall surrender, properly
endorsed, the certificate or certificates to be so exchanged. Thereupon, the
Company shall execute and deliver to the person entitled thereto a new Warrant
certificate or certificates, as the case may be, as so requested. Any Warrant
issued upon exchange, transfer or partial exercise of the Warrants shall be the
valid obligation of the Company, evidencing the same generic rights and entitled
to the same generic benefits under this Warrant Agreement as the Warrants
surrendered for such exchange, transfer or exercise.

    6. TRANSFER OF WARRANTS. Subject to the provisions of Section 14 hereof, the
Warrants shall be transferrable only on the Warrant Register upon delivery to
the Company of the Warrant certificate or certificates duly endorsed by the
Warrant Holder or by his duly authorized attorney-in-fact or legal
representative, or accompanied by proper evidence of succession, assignment or
authority to transfer. In all cases of transfer by an attorney-in-fact, the
original power of attorney, duly approved, or an official copy thereof duly
certified, shall be deposited with the Company. In case of transfer by
executors, administrators, guardians or other legal representatives, duly
authenticated evidence of their authority shall be produced, and may be required
to be deposited with the Company in its discretion. Upon any registration of
transfer, the Company shall deliver a new Warrant or Warrants to the person
entitled thereto.

     7.   TERM OF WARRANTS:  EXERCISE OF WARRANTS.

     (a)  Each Warrant entitles the Warrant Holder thereof to purchase one share
of Common Stock during the time period and subject to the conditions set forth 
in the respective Warrant Certificates at a exercise price of $1.00 per share, 
subject to adjustment in accordance with Section 12 hereof (the "Exercise 
Price").  Each Warrant terminates on the tenth anniversary of the date on which 
such Warrant becomes exercisable in accordance with its terms (the "Expiration 
Date").

     (b) The Exercise Price and the number of shares issuable upon exercise of
Warrants are subject to adjustment upon the occurrence of certain events,
pursuant to the provisions of Section 12 of this Warrant Agreement. Subject to
the provisions of this Warrant Agreement, each Warrant Holder shall have the
right, which may be exercised as expressed in such Warrants to purchase from the
Company (and the Company shall issue and sell to such Warrant Holder) the number
of fully paid and nonassessable shares of Common Stock specified in such
Warrants, upon surrender to the Company, or its duly authorized agent, of such
Warrants, with the purchase form on the reverse thereof duly filled in and
signed, and upon payment to the Company of the Exercise Price, as

                                      -3-
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adjusted in accordance with the provisions of Section 12 of this Warrant 
Agreement or upon a net exercise pursuant to this subsection of this Warrant 
Agreement, for the number of shares in respect of which such Warrants are then 
exercised.  The Warrant Holder may (i) pay the Exercise Price in cash, by 
certified or official bank check payable to the order of the Company, or (ii) 
make an exercise of Warrants for "Net Warrant Shares."  The number of Net 
Warrant Shares will be determined as described by the following formula:  Net 
Warrant Shares = [WS x (MP-EP)]/MP.  "WS" is the number of Warrant Shares 
issuable upon exercise of the Warrants or portion of Warrants in question.  "MP"
is the Market Price of the Common Stock on the last trading day preceding the 
date of the request to exercise the Warrants.  "Market Price" shall mean the 
then current market price per share of Common Stock, as determined in paragraph 
12.1(e).  "EP" shall mean the Exercise Price.

     Upon such surrender of Warrants, and payment of the Exercise Price, with 
cash or securities, or upon a net exercise as aforesaid, the Company at its 
expense shall issue and cause to be delivered with all reasonable dispatch to or
upon the written order of the Warrant Holder and in such name or names as the
Warrant Holder may designate, a certificate or certificates for the number of
full shares of Common Stock so purchased upon the exercise of such Warrants,
together with cash, as provided in Section 12 of this Warrant Agreement, in
respect of any fraction of a share of such stock otherwise issuable upon such
surrender. Such certificate or certificates shall be deemed to have been issued,
and any person so designated to be named therein shall be deemed to have become
a holder of record of such shares, as of the date of the surrender of such
Warrants and payment of the Exercise Price or receipt of shares by net exercise
as aforesaid. The rights of purchase represented by the Warrants shall be
exercisable, at the election of the Warrant Holders thereof, either in full or
from time to time in part and, in the event that any Warrant is exercised in
respect of less than all of the shares purchasable on such exercise at any time
prior to the Expiration Date, a new certificate evidencing the remaining Warrant
or Warrants will be issued.

     8. COMPLIANCE WITH GOVERNMENT REGULATIONS. The Company covenants that if
any share of Common Stock required to be reserved for purposes of exercise or
conversion of Warrants require, under any federal or state law or applicable
governing rule or regulation or any national securities exchange, registration
with or approval of any governmental authority or listing on any such national
securities exchange, before such shares may be issued upon exercise, the Company
will use its commercially reasonable efforts to cause such shares to be duly
registered, approved or listed on the relevant national securities exchange, as
the case may be.

     9.  PAYMENT OF TAXES.  The Company will pay all documentary stamp taxes, if
any, attributable to the initial issuance of Warrant Shares upon the exercise of
Warrants and any securities issued pursuant to Section 12 hereof; provided, 
however, that the Company shall not be required to pay any tax or taxes which 
may be payable in respect of any transfer involved in the issue or delivery of 
any Warrants or certificates for Warrant Shares and any securities issued 
pursuant to Section 12 hereof in a name other than that of the Warrant Holder of
such Warrants.

    10.  MUTILATED OR MISSING WARRANTS.  In case any of the Warrants shall be 
mutilated, lost, stolen or destroyed, the Company shall issue and deliver in 
exchange and substitution for and upon cancellation of the mutilated Warrant, or
in lieu of and in substitution for the Warrant lost, stolen or destroyed, a new 
Warrant of like tenor and representing an equivalent right or interest.

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        11. RESERVATION OF WARRANT SHARES; PURCHASE AND CANCELLATION OF 
WARRANTS. The Company shall at all times reserve, out of the authorized and 
unissued shares of Common Stock, a number of shares sufficient to provide for 
the exercise of the rights of purchase represented by the Warrants, and the 
transfer agent for the Common Stock ("Transfer Agent") and every subsequent 
transfer agent for any shares of the Company's capital stock issuable upon the 
exercise of any of the rights of purchase aforesaid are hereby irrevocably 
authorized and directed at all times until the Expiration Date to reserve such 
number of authorized and unissued shares as shall be requisite for such purpose.
The Company will keep a copy of this Warrant Agreement on file with the Transfer
Agent and with every subsequent transfer agent for any shares of the Company's
capital stock issuable upon the exercise of the rights of purchase represented
by the Warrants. The Company will supply the Transfer Agent and any such
subsequent transfer agent with duly executed stock certificates for such purpose
and will itself provide or otherwise make available any cash which may be
issuable as provided by Section 13 of this Warrant Agreement. The Company will
furnish to the Transfer Agent and any such subsequent transfer agent a copy of
all notices of adjustments, and certificates related thereto, transmitted to
each Warrant Holder pursuant to Section 12.3 hereof. All warrants surrendered in
the exercise of the rights thereby evidenced shall be canceled, and such
canceled Warrants shall constitute sufficient evidence of the number of shares
of stock which have been issued upon the exercise of such Warrants (subject to
adjustment as herein provided). No shares of stock shall be subject to
reservation in respect of the Warrants subsequent to the Expiration Date except
to the extent necessary to comply with the terms of this Warrant Agreement.

        12. ADJUSTMENT OF EXERCISE PRICE AND NUMBER OF WARRANT SHARES. The 
number and kind of securities purchasable upon the exercise of each Warrant and
the Exercise Price shall be subject to adjustment from to time upon the
occurrence of certain events, as hereafter defined.

                12.1. MECHANICAL ADJUSTMENTS. The number of Warrant Shares 
        purchasable upon the exercise of each Warrant and the Warrant Price
        shall be subject to adjustment as follows:

                        (a) In case the Company shall (i) pay a dividend to 
                holders of Common Stock in shares of Common Stock or make a
                distribution to holders of Common Stock in shares of Common
                Stock, (ii) subdivide its outstanding shares of Common Stock 
                into a larger number of shares of Common Stock, (iii) combine
                its outstanding shares of Common Stock into a smaller number of
                shares of Common Stock or (iv) issue by reclassification of its
                shares of Common Stock other securities of the Company
                (including any such classification in connection with a
                consolidation or merger in which the Company is the surviving
                corporation), the number of Warrant Shares purchasable upon
                exercise of each Warrant immediately prior thereto shall be
                adjusted so that the Warrant Holder shall be entitled to receive
                the kind and number of Warrant Shares or other securities of the
                Company which he would have owned or have been entitled to
                receive after the happening of any of the events described
                above, had such Warrant been exercised immediately prior to the
                happening of such event or any record date with respect thereto
                regardless of whether the Warrants are exercisable at the time
                of the happening of such event or at the time of any record date
                with respect thereto. An adjustment made pursuant to this
                paragraph (a) shall become effective immediately after the
                effective date of such event retroactive to the record date, if
                any, for such event.

                                     -5- 

<PAGE>
 
           (b) In case the Company shall issue rights, options, or warrants to 
     holders of its outstanding Common Stock, without any charge to such
     holders, entitling them to subscribe for or purchase shares of Common Stock
     at a price per share which is lower at the record date mentioned below than
     the Exercise Price, then (i) the Exercise in effect immediately prior to
     such issuance shall immediately be reduced to the price that is equivalent
     to such consideration received by the Company upon such issuance and (ii)
     the number of Warrant Shares thereafter purchasable upon the exercise of
     each Warrant shall be increased in direct proportion to the increase in the
     number of shares of Common Stock outstanding on a fully diluted basis
     immediately prior to such issuance; provided that if such shares of Common
     Stock, options or other convertible securities (other than Excluded Stock
     (as defined in the Note Purchase Agreement)) are issued for consideration
     per share less than the Exercise Price at the date of such issue or sale,
     the number of shares of Common Stock that immediately prior to such
     issuance the Warrant Holder shall have been entitled to purchase pursuant
     to this Warrant shall be increased to the greater of (i) that number of
     shares of Common Stock that immediately prior to such issuance the Warrant
     Holder shall have been entitled to purchase pursuant to this Warrant
     multiplied by a fraction, the numerator of which is the Exercise Price and
     the denominator of which is such consideration per share, and (ii) the
     number of shares of Common Stock otherwise calculated under this Section
     12.1. Such adjustment shall be made whenever such rights, options, or
     warrants are issued, and shall become effective immediately after the
     record date for the determination of stockholders entitled to receive such
     rights, options, or warrants; provided that this Section 12.1(b) shall
     expire and be of no force and effect on or after April 1, 1998.

          (c) In case the Company shall distribute to holders of its shares of
     Common Stock, evidences of its indebtedness or assets (including cash
     dividends or other cash distributions), or rights, options, or warrants, or
     convertible or exchangeable securities containing the right to subscribe
     for or purchase shares of Common Stock (excluding those referred to in
     paragraph (b) above), then in each case the number of Warrant Shares
     thereafter purchasable upon the exercise of each Warrant shall be
     determined by multiplying the number of Warrant Shares theretofore
     purchasable upon the exercise of each Warrant by a fraction, of which the
     numerator shall be the then current market price per share of Common Stock
     (as determined in accordance with paragraph (e) below) on the date of such
     distribution, and of which the denominator shall be the then current market
     price per share of Common Stock, less the then fair value (as determined in
     good faith by the Board of Directors of the Company) of the portion of the
     assets or evidences of indebtedness so distributed or of such subscription
     rights, options, or warrants, or of such convertible or exchangeable
     securities applicable to one share of Common Stock. Such adjustment shall
     be made whenever any such distribution is made, and shall become effective
     on the date of distribution retroactive to the record date for the
     determination of stockholders entitled to receive such distribution.

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         In the event of distribution by the Company to holders of its shares of
     Common Stock of stock of a subsidiary or securities convertible into or
     exercisable for such stock, then in lieu of an adjustment in the number of
     Warrant Shares purchasable upon the exercise of each Warrant, the Warrant
     Holder, upon the exercise thereof at any time after such distribution,
     shall be entitled to receive from the Company, such subsidiary, or both, as
     the Company shall determine, the stock or other securities to which such
     Warrant Holder would have been entitled if such Warrant Holder had
     exercised such Warrant immediately prior thereto regardless of whether the
     Warrants are exercisable at such time, all subject to further adjustment as
     provided in this subsection 12.1; provided, however, that no adjustment in
     respect of dividends or interest on such stock or other securities shall be
     made during the term of a Warrant or upon the exercise of a Warrant;
     provided further that this Section 12.1(c) shall expire and be of no force
     and effect on or after April 1, 1998.

         (d) In case the Company shall sell and issue shares of Common Stock
     (other than pursuant to rights, options, warrants, or convertible
     securities initially issued before the date of this Agreement) or rights,
     options, warrants, or convertible securities containing the right to
     subscribe for or purchase shares of Common Stock (excluding shares, rights,
     options, warrants, or convertible securities issued in any of the
     transactions described in paragraphs (a), (b) or (c) above) at a price per
     share of Common Stock (determined in the case of such rights, options,
     warrants or convertible securities, by dividing (w) the total of the amount
     received or receivable by the Company (determined as provided below) in
     consideration of the sale and issuance of such rights, options, warrants,
     or convertible securities, by (x) the total number of shares of Common
     Stock covered by such rights, options, warrants, or convertible securities)
     lower than the Exercise Price in effect immediately prior to such sale and
     issuance, then (i) the Exercise in effect immediately prior to such
     issuance shall immediately be reduced to the price that is equivalent to
     such consideration received by the Company upon such issuance and (ii) the
     number of Warrant Shares thereafter purchasable upon the exercise of the
     Warrants shall be increased in direct proportion to the increase in the
     number of shares of Common Stock outstanding on a fully diluted basis
     immediately prior to such issuance; provided that if such shares of Common
     Stock, options or other convertible securities (other than Excluded Stock)
     are issued for consideration per share less than the Exercise Price at the
     date of such issue or sale, the number of shares of Common Stock that
     immediately prior to such issuance the Warrant Holder shall have been
     entitled to purchase pursuant to this Warrant shall be increased to the
     greater of (i) that number of shares of Common Stock that immediately prior
     to such issuance the Warrant Holder shall have been entitled to purchase
     pursuant to this Warrant multiplied by a fraction, the numerator of which
     is the Exercise Price and the denominator of which is such consideration
     per share, and (ii) the number of shares of Common Stock otherwise
     calculated under this Section 12.1. Such adjustment shall be made
     successively whenever such as issuance is made; provided that this Section
     12.1(d) shall expire and be of no force and effect on or after April 1,
     1998. For the purposes of such adjustments, the consideration received or
     receivable by the Company for rights, options, warrants, or convertible
     securities shall be deemed to

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<PAGE>
 
     be the consideration received by the Company for such rights, options,
     warrants, or convertible securities, plus the consideration or premiums
     stated in such rights, options, warrants, or convertible securities to be
     paid for the shares of Common Stock covered thereby. In case the Company
     shall sell and issue shares of Common Stock, or rights, options, warrants,
     or convertible securities containing the right to subscribe for or purchase
     shares of Common Stock, for a consideration consisting, in whole or in
     part, of property other than cash or its equivalent, then in determining
     the "price per share of Common Stock" and the "consideration received or
     receivable by the Company" for purposes of the first sentence of this
     paragraph (d), the Board of Directors shall determine, in its discretion,
     the fair value of said property.

          (e) For the purpose of any computation under paragraphs (b), (c), and 
     (d) of this Section, the current market price per share of Common Stock at
     any date shall be the average of the daily closing prices of the Company's
     Common Stock, for five consecutive trading days ending one trading day
     before the date of such computation. The closing price for each day shall
     be the last such reported sales price regular way or, in case no such
     reported sale takes place on such day, the average of the closing bid and
     asked prices regular way for such day, in each case on the principal
     national securities exchange on which the shares of Common Stock are listed
     or admitted to trading or, if not listed or admitted to trading, the
     average of the closing bid and asked prices of the Common Stock in the
     over-the-counter market as reported by NASDAQ or any comparable system. In
     the absence of one or more such quotations, the Board of Directors of the
     Company shall determine the current market price, in good faith, on the
     basis of such quotations as it considers appropriate. Notwithstanding the
     foregoing, for the purpose of any calculation under paragraph (d) above (A)
     with respect to any issuance of options under the Company's employee or
     director compensation stock option plans as in effect or as adopted by the
     Board of Directors of the Company on the date hereof, the term "current
     market price", in such instances, shall mean the fair market price on the
     date of the issuance of any such option determined in accordance with the
     Company's employee compensation stock option plans as in effect or adopted
     by the Board of Directors of the Company on the date hereof; and (B) with
     respect to any issuances of Common Stock (or rights, options, warrants, or
     convertible securities containing the right to subscribe for or purchase
     shares of Common Stock) in connection with bona fide corporate transactions
     (other than issuances in such transactions for cash or similar
     consideration), the term "fair market price" shall mean the fair market
     price per share as determined in arm's-length negotiations by the Company
     and such other parties (other than affiliates or subsidiaries of the
     Company) to such transactions as reflected in the definitive documentation
     with respect thereto, unless such determination is not reasonably related
     to the closing market price on the date of such determination.

          (f) In any case in which this Section 12.1 shall require that any 
     adjustment in the number of Warrant Shares be made effective as of
     immediately after a record date for a specified event, the Company may
     elect to defer until the occurrence of the event the issuing to the holder
     of any Warrant exercised after that record date the shares of Common Stock
     and other securities of the Company, if any,

                                      -8-
<PAGE>
 
     issuable upon the exercise of any Warrant over and above the shares of
     Common Stock and other securities of the Company, if any, issuable upon the
     exercise of any Warrant prior to such adjustment; provided, however, that
     the Company shall deliver to such Warrant Holder a due bill or other
     appropriate instrument evidencing the holder's right to receive such
     additional shares or securities upon the occurrence of the event requiring
     such adjustment.

          (g) No adjustment in the number of Warrant Shares purchasable
     hereunder shall be required unless such adjustment would require an
     increase or decrease of at least one percent (1%) in the number of Warrant
     Shares purchasable upon the exercise of each Warrant; provided, however,
     that any adjustments which by reason of this paragraph (g) are not required
     to be made shall be carried forward and taken into account in any
     subsequent adjustment. All calculations shall be made to the nearest one-
     thousandth of a share.

          (h) Whenever the number of Warrant Shares purchasable upon the
     exercise of each Warrant is adjusted, as herein provided, the Warrant Price
     payable upon the exercise of each Warrant shall be adjusted by multiplying
     such Warrant Price immediately prior to such adjustment by a fraction, of
     which the numerator shall be the number of Warrant Shares purchasable upon
     the exercise of such Warrant immediately prior to such adjustment, and of
     which the denominator shall be the number of Warrant Shares purchasable
     immediately.

          (i) No adjustment in the number of Warrant Shares purchasable upon the
     exercise of each Warrant need be made under paragraphs (b), (c) and (d) if
     the Company issues or distributes to each Warrant Holder the rights,
     options, warrants, or convertible or exchangeable securities, or evidences
     of indebtedness or assets referred to in those paragraphs which each
     Warrant Holder would have been entitled to receive had the Warrants been
     exercised prior to the happening of such event or the record date with
     respect thereto regardless of whether the Warrants are exercisable at the
     time of the happening of such event or at the time of any record date with
     respect thereto. No adjustment need be made for a change in the par value
     of the Warrant Shares.

          (j) For the purpose of this Section 12.1, the terms "shares of Common
     Stock" shall mean (i) the class of stock designated as the Common Stock of
     the Company at the date of this Agreement, or (ii) any other class of stock
     resulting from successive changes or reclassifications of such shares
     consisting solely of changes in par value, or from par value to no par
     value, or from no par value to par value. In the event that at any time, as
     a result of an adjustment made pursuant to paragraph (a) above, the Warrant
     Holders shall become entitled to purchase any securities of the Company
     other than shares of Common Stock, thereafter the number of such other
     securities so purchasable upon exercise of each Warrant and the Exercise
     Price of such securities shall be subject to adjustment from time to time
     in a manner and on terms as nearly equivalent as practicable to the
     provisions with respect to the Warrant Shares contained in paragraphs (a)
     through (i), inclusive, above, and the provisions

                                      -9-
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     of Section 7 and Section 12.2 through 12.5, inclusive, with respect to the 
     Warrant Shares, shall apply on like terms to any such other securities.

          (k) Upon the expiration of any rights, options, warrants, or
     conversion or exchange privileges, if any thereof shall not have been
     exercised, the Warrant Price and the number of shares of Common Stock
     purchasable upon the exercise of each warrant shall, upon such expiration,
     be readjusted and shall thereafter be such as it would have been had it
     been originally adjusted (or had the original adjustment not been required,
     as the case may be) as if (A) the only shares of Common Stock so issued
     were the shares of Common Stock, if any, actually issued or sold upon the
     exercise of such rights, options, warrants, or conversion on exchange
     rights and (B) such shares of Common Stock, if any, were issued or sold for
     the consideration actually received by the Company upon such exercise plus
     the aggregate consideration, if any, actually received by the Company for
     the issuance, sale or grant of all such rights, options, warrants, or
     conversion or exchange rights whether or not exercised; provided, however,
     that no such readjustment shall have the effect of increasing the Warrant
     Price or decreasing the number of Warrant Shares by an amount in excess of
     the amount of the adjustment initially made with respect to the issuance,
     sale or grant of such rights, options, warrants, or conversion or exchange
     rights.

          (l) In addition to the adjustments set forth above, the Exercise Price
     shall be immediately reduced and the number of Warrant Shares shall be
     immediately increased, in each case, or a pari passu basis with the
     conversion, exercise, or strike price of any other derivative securities of
     the Company whether now outstanding or hereafter issued.

     12.2. VOLUNTARY ADJUSTMENT BY THE COMPANY. The Company may, at its option, 
at any time during the term of the Warrants, reduce the then current Exercise 
Price to any amount determined appropriate by the Board of Directors of the 
Company.

     12.3. NOTICE OF ADJUSTMENT. When the number of Warrant Shares purchasable 
upon the exercise of each Warrant or the Exercise Price of such Warrant Shares 
is adjusted, as herein provided, the Company shall promptly mail by first class,
postage prepaid, to each Warrant Holder notice of such adjustment or adjustments
and a certificate of a firm of independent public accountants selected by the 
Board of Directors of the Company (who may be the regular accountants employed 
by the Company) setting forth the number of Warrant Shares purchasable upon the 
exercise of each Warrant and the Exercise Price of such Warrant Shares after 
such adjustment and setting forth a brief statement of the facts requiring such 
adjustment and setting forth the computation by which such adjustment was made. 
Such certificate, absent manifest error, shall be conclusive evidence of the 
correctness of such adjustment.

     12.4. PRESERVATION OF PURCHASE RIGHTS UPON MERGER, CONSOLIDATION, ETC. In 
case of any consolidation of the Company with or merger of the Company into 
another person or in case of any sale, transfer, or lease to another person of 
all or substantially all

                                     -10-
<PAGE>
 
     the assets of the Company, the Company or such successor or purchaser, as
     the case may be, shall execute with each Warrant Holder an agreement that
     each Warrant Holder shall have the right thereafter upon payment of the
     Exercise Price in effect immediately prior to such action to purchase upon
     exercise of each Warrant the kind and amount of shares and other securities
     and property which the Warrant Holder would have owned or have been
     entitled to receive after the happening of such consolidation, merger,
     sale, transfer, or lease had such Warrant been exercised immediately prior
     to such action regardless of whether the Warrants are exercisable at the
     time of such action. Such agreement shall provide for adjustments, which
     shall be as nearly equivalent as may be practicable to the adjustments
     provided for in this Section 12. The provisions of this Section 12.4 shall
     similarly apply to successive consolidations, mergers, sales, transfers, or
     leases.

          12.5 STATEMENT ON WARRANTS. Even though Warrants heretofore or
     hereafter issued may continue to express the same price and number and kind
     of shares as are stated in the Warrants initially issuable pursuant to this
     Warrant Agreement, the parties understand and agree that such Warrants will
     represent rights consistent with any adjustments in the Exercise Price or
     the number or kind of shares purchasable upon the exercise of the Warrants.

     13. FRACTIONAL INTERESTS. The Company shall not be required to issue 
fractional Warrant Shares on the exercise of Warrants. If more than one Warrant 
shall be presented for exercise in full at the same time by the same Warrant 
Holder, the number of full Warrant Shares which shall be issuable upon the 
exercise thereof shall be computed on the basis of the aggregate number of 
Warrant Shares purchasable on exercise of the Warrants so presented. If any 
fraction of a Warrant Share would, except for the provisions of this Section 13,
be issuable on the exercise of any Warrant (or specified portion, thereof), the 
Company shall pay an amount in cash equal to the closing price for one share of 
the Common Stock on the trading day immediately preceding the date the Warrant 
is presented for exercise, multiplied by such fraction.

     14. REGISTRATION UNDER THE SECURITIES ACT OF 1933. Willis represents and 
warrants to the Company that it will not dispose of the Warrant or Warrant 
Shares except pursuant to (i) an effective registration statement, or (ii) an 
applicable exemption from registration under the Securities Act of 1933 (the 
"Act"). In connection with any sale by Willis pursuant to clause (ii) of the 
preceding sentence, it shall furnish to the Company an opinion of counsel 
reasonably satisfactory to the Company to the effect that such exemption from 
registration is available in connection with such sale.

     15. CERTIFICATE TO BEAR LEGENDS. The Warrants shall be subject to a 
stop-transfer order and the certificate or certificates therefor shall bear the 
following legend by which each Warrant Holder shall be bound:

     "THE WARRANTS REPRESENTED HEREBY AND THE SECURITIES ISSUABLE UPON EXERCISE 
HEREOF HAVE NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933, AS AMENDED 
(THE "SECURITIES ACT"), OR THE SECURITIES LAWS OF ANY OTHER STATE. THE WARRANTS 
REPRESENTED HEREBY AND THE

                                     -11-
    
<PAGE>
 
     SECURITIES ISSUABLE UPON EXERCISE HEREOF HAVE BEEN ACQUIRED FOR INVESTMENT
     AND MAY NOT BE SOLD OR OFFERED FOR SALE OR OTHERWISE TRANSFERRED, EXCEPT
     PURSUANT TO (i) AN EFFECTIVE REGISTRATION STATEMENT UNDER THE SECURITIES
     ACT, OR (ii) AN APPLICABLE EXEMPTION FROM REGISTRATION UNDER THE SECURITIES
     ACT. ANY SALE PURSUANT TO CLAUSE (ii) OF THE PRECEDING SENTENCE MUST BE
     ACCOMPANIED BY AN OPINION OF COUNSEL REASONABLY SATISFACTORY TO THE COMPANY
     TO THE EFFECT THAT SUCH EXEMPTION FROM REGISTRATION IS AVAILABLE IN
     CONNECTION WITH SUCH SALE."

     The Warrant Shares or other securities issued upon exercise of the Warrants
shall, unless issued pursuant to an effective registration statement, be subject
to a stop-transfer order and the certificate or certificates evidencing any such
Warrant Shares or securities shall bear the following legend by which the 
Warrant Holder thereof shall be bound:

     "THE SECURITIES REPRESENTED HEREBY HAVE BEEN ACQUIRED FOR INVESTMENT AND
     MAY NOT BE SOLD OR OFFERED FOR SALE OR OTHERWISE TRANSFERRED, EXCEPT
     PURSUANT TO (i) AN EFFECTIVE REGISTRATION STATEMENT UNDER THE SECURITIES
     ACT, OR (ii) AN APPLICABLE EXEMPTION FROM REGISTRATION UNDER THE SECURITIES
     ACT. ANY SALE PURSUANT TO CLAUSE (ii) OF THE PRECEDING SENTENCE MUST BE
     ACCOMPANIED BY AN OPINION OF COUNSEL REASONABLY SATISFACTORY TO THE COMPANY
     TO THE EFFECT THAT SUCH EXEMPTION FROM REGISTRATION IS AVAILABLE IN
     CONNECTION WITH SUCH SALE."

     16. REGISTRATION RIGHTS. The Warrant Shares shall be covered by and subject
to the registration rights set forth in Section 4.1.11 of the Note Purchase 
Agreement.

     17. NO RIGHTS AS STOCKHOLDERS; NOTICE TO WARRANT HOLDERS. Nothing contained
in this Warrant Agreement or in any of the Warrants shall be construed as 
conferring upon the Warrant Holders or their transferees the right to vote or to
receive dividends or to consent or to receive notice as stockholders in respect 
of any meeting of stockholders for the election of directors of the Company or 
any other matter, or any rights whatsoever as stockholders of the Company. If, 
however, at any time prior to the expiration of the Warrants and prior to their 
exercise, any of the following events shall occur:

          (a) the Company shall declare any dividend payable in any securities
     upon its shares of Common Stock or make any distribution (other than a cash
     dividend) to the holders of its shares of Common Stock; or

          (b) the Company shall offer to the holders of its shares of Common
     Stock any additional shares of Common Stock or securities convertible into
     or exchangeable for shares of Common Stock or any right to subscribe to or
     purchase any thereof; or

                                     -12-
<PAGE>
 
          (c) a dissolution, liquidation, or winding up of the Company (other
     than in connection with a consolidation, merger, sale, transfer, or lease
     or all or substantially all of its property, assets, and business as an
     entirety) shall be proposed,

then in any one or more of said events the Company shall give notice in writing 
of such event to the Warrant Holders as provided in Section 20 hereof, with such
notice to be completed at least 15 days prior to the date fixed as a record date
or the date of closing the transfer books for the determination of the 
stockholders entitled to such dividend, distribution, or subscription rights,
or for the determination of stockholders entitled to vote on such proposed
dissolution, liquidation or winding up. Such notice shall specify such record
date or the date of closing the transfer books, as the case may be. Failure to
provide or receive such notice on any defect therein or in the mailing thereof
shall not affect the validity of any action taken in connection with such
dividend, distribution, or subscription rights, or such proposed dissolution,
liquidation, or winding up.

     18.  EXPENSES.  The Company shall pay all legal and other reasonable 
out-of-pocket expenses of the Warrant Holders and of their counsel (up to a 
maximum of $25,000).  The Company agrees to reimburse Willis upon demand for its
reasonable out-of-pocket costs and expenses incurred in connection with the 
preparation, review, negotiation, execution, and delivery of this Warrant 
Agreement and all other related documents.

    19.  RIGHT TO INFORMATION.  The Company, in accordance with Section 16(c) 
above, will provide to all Warrant Holders and to all holders of Warrant Shares,
on a timely basis, copies of all documents and reports delivered to its
shareholders.

     20.  NOTICES.  Any notice pursuant to this Warrant Agreement to be given 
or made by the holder of any Warrant or Warrant Shares in or on the Company 
shall be sufficiently given or made if sent by first-class mail, postage 
prepaid, addressed as follows:

                            EqualNet Holding Corp.
                          1250 Wood Branch Park Drive
                             Houston, Texas 77079
                          Attention:  General Counsel

Notices or demands authorized by this Warrant Agreement to be given or made to 
or on the Warrant Holder of any Warrant or Warrant Shares shall be sufficiently 
given or made (except as otherwise provided in this Warrant Agreement) if sent 
by registered mail, return receipt requested, postage prepaid, addressed to such
Warrant Holder at the address of such Warrant Holder as shown on the Warrant
Register or the Common Stock Register, as the case may be.

     21.  GOVERNING LAW.  THIS WARRANT AGREEMENT, THE WARRANTS AND ALL RELATED 
DOCUMENTS SHALL BE DEEMED TO BE CONTRACTS MADE UNDER AND SHALL BE CONSTRUED IN 
ACCORDANCE WITH AND GOVERNED BY THE LAWS OF THE STATE OF TEXAS, WITHOUT GIVING 
EFFECT TO PRINCIPLES OF CONFLICTS OF LAW.  ANY DISPUTE HEREUNDER OR UNDER THE 
WARRANTS OR RELATED DOCUMENTS SHALL BE DETERMINED EXCLUSIVELY IN ACCORDANCE WITH
SECTION 8.7 OF THE NOTE PURCHASE AGREEMENT.

                                     -13-
<PAGE>
 
     22.  SUPPLEMENTS AND AMENDMENTS.  The Company and the Warrant Holders may 
from time to time supplement or amend this Warrant Agreement in order to cure 
any ambiguity or to correct or supplement any provision contained herein which 
may be defective or inconsistent with any other provision herein, or to make any
other provisions in regard to matters or questions arising hereunder which the 
Company and the Warrant Holder may deem necessary or desirable and which shall 
not be inconsistent with the provisions of the Warrants and which shall not 
adversely affect the interests of the Warrant Holders.  Any amendment to this 
Warrant Agreement may be effected with the consent of Warrant Holders of at 
least a majority of the total then outstanding Warrants (for this purpose 
Warrant Shares shall be deemed to be Warrants in the proportion that Warrant 
Shares are then issuable upon the exercise of Warrants); provided that any 
amendment which shall have the effect of materially adversely affecting the 
interests of any Warrant Holder shall not be effective with respect to such 
Warrant Holder if such Warrant Holder shall not have consented thereto.

     23. SURVIVAL OF COVENANTS. All covenants and agreements made herein shall
survive the execution and delivery of this Warrant Agreement and the Warrants
and shall remain in force and effect until the Expiration Date of all Warrants.

     24. SUCCESSORS. All representations and warranties of the Company and all
covenants and agreements of this Warrant Agreement by or for the benefit of the
Company or the Warrant Holders shall bind and inure to the benefit of their
respective successors and assigns hereunder.

     25.  BENEFITS OF THIS WARRANT AGREEMENT.  Nothing in this Warrant 
Agreement shall be construed to give to any person or corporation other than the
Company and the Warrant Holders, any legal or equitable right, remedy, or claim 
under this Warrant Agreement, but this Warrant Agreement shall be for the sole 
and exclusive benefit of the Company and the holders of the Warrants and Warrant
Shares.

     26.  CAPTIONS.  The captions of the sections and subsections of this 
Warrant Agreement have been inserted for convenience and shall have no 
substantive effect.

     27.  COUNTERPARTS.  This Warrant Agreement may be executed in any number of
counterparts, each of which so executed shall be deemed to be an original, but 
such counterparts together shall constitute but one and the same instrument.

                                     -14-
<PAGE>
 
     IN WITNESS WHEREOF, the parties hereto have caused this Warrant Agreement 
to be duly executed on the day, month and year first above written.

                                  EQUALNET HOLDING CORP.


                                  By:            /s/ Michael L. Hlinak
                                         ---------------------------------------
                                  Name:            Michael L. Hlinak
                                         ---------------------------------------
                                  Title:       Chief Operating Officer
                                         ---------------------------------------


                                  ----------------------------------------------
                                  MICHAEL T. WILLIS

                                     -15-
<PAGE>
 
                                   EXHIBIT A

                                    FORM OF
                              WARRANT CERTIFICATE

THE WARRANTS REPRESENTED HEREBY AND THE SECURITIES ISSUABLE UPON EXERCISE HEREOF
HAVE NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933, AS AMENDED (THE 
"SECURITIES ACT"), OR THE SECURITIES LAWS OF ANY OTHER STATE. THE WARRANTS 
REPRESENTED HEREBY AND THE SECURITIES ISSUABLE UPON EXERCISE HEREOF HAVE BEEN 
ACQUIRED FOR INVESTMENT AND MAY NOT BE SOLD OR OFFERED FOR SALE OR OTHERWISE 
TRANSFERRED, EXCEPT PURSUANT TO (i) AN EFFECTIVE REGISTRATION STATEMENT UNDER 
THE SECURITIES ACT, OR (ii) AN APPLICABLE EXEMPTION FROM REGISTRATION UNDER THE 
SECURITIES ACT. ANY SALE PURSUANT TO CLAUSE (ii) OF THE PRECEDING SENTENCE MUST 
BE ACCOMPANIED BY AN OPINION OF COUNSEL REASONABLY SATISFACTORY TO THE COMPANY 
TO THE EFFECT THAT SUCH EXEMPTION FROM REGISTRATION IS AVAILABLE IN CONNECTION 
WITH SUCH SALE.

THE TRANSFER OR EXCHANGE OF THE WARRANTS AND COMMON STOCK UNDERLYING SUCH 
WARRANTS REPRESENTED BY THIS CERTIFICATE IS RESTRICTED IN ACCORDANCE WITH THE 
WARRANT AGREEMENT REFERRED TO HEREIN.

    No. _________________                                    500,000 Warrants

                      VOID AFTER 5:00 P.M. NEW YORK, TIME
                               ON MARCH 4, 2003
                            EQUALNET HOLDING CORP.
                              WARRANT CERTIFICATE

     THIS CERTIFIES THAT for value received MICHAEL T. WILLIS the registered 
holder hereof or registered assigns (the "Warrant Holder"), is the owner of the 
number of the Warrants set forth above, each of which entitles the owner thereof
to purchase at any time from 9:00 A.M., New York time, on March 5, 1998 until
5:00 P.M., New York time on March 4, 2008 one fully paid and nonassessable share
of the common stock (subject to adjustment), par value $0.01 per share (the
"Common Stock"), of EQUALNET HOLDING CORP., a Texas corporation (the "Company"),
at the exercise price of $1.00 per share, subject to adjustment and limitation
as described in the Warrant Agreement referred to below (the "Exercise Price").
The Warrant Holder may pay the Exercise Price in cash, or by certified or
official bank check or make a net exercise for Net Warrant Shares as described
in the Warrant Agreement.

     This Warrant Certificate is subject to, and entitled to the benefits of, 
all of the terms, provisions and conditions of an agreement dated March 5, 1998 
(the "Warrant Agreement"), between the Company and Michael T. Willis, which 
Warrant Agreement is hereby incorporated herein by reference and made a part 
hereof and to which Warrant Agreement reference is hereby made for a

                                      -1-
<PAGE>
 
full description of the rights, limitations of rights, obligations, duties and 
immunities hereunder of the Company and the Warrant Holders of the Warrant 
Certificates. Copies of the Warrant Agreement are on file at the principal 
office of the Company.

     The Warrant Holder hereof may be treated by the Company and all other 
persons dealing with this Warrant Certificate as the absolute owner hereof for 
any purpose and as the person entitled to exercise the rights represented 
hereby, or to the transfer hereof on the books of the Company, any notice to the
contrary notwithstanding, and until such transfer on such books, the Company may
treat the Warrant Holder hereof as the owner for all purposes.

     The Warrant Certificate, with or without other Warrant Certificates, upon 
surrender at the principal office of the Company, may be exchanged for another 
Warrant Certificate or Warrant Certificates of like tenor and date evidencing 
Warrants entitling the Warrant Holder to purchase a like aggregate number of 
shares of Common Stock as the Warrants evidenced by the Warrant Certificate or 
Warrant Certificates surrendered entitled to such Warrant Holder to purchase. If
this Warrant Certificate shall be exercised in part, the Warrant Holder shall be
entitled to receive upon surrender hereof, another Warrant Certificate or 
Warrant Certificates for the number of whole Warrants not exercised.

     No fractional shares of Common Stock will be issued upon the exercise of 
any Warrant or Warrants evidenced hereby, but in lieu thereof a cash payment 
will be made as provided in the Warrant Agreement.

     Neither the Warrants nor the Warrant Certificate entitles any Warrant 
Holder hereof to any of the rights of a stockholder of the Company.

     THIS WARRANT SHALL BE DEEMED TO BE A CONTRACT MADE UNDER AND SHALL BE 
CONSTRUED IN ACCORDANCE WITH AND GOVERNED BY THE LAWS OF THE STATE OF TEXAS, 
WITHOUT GIVING EFFECT TO PRINCIPLES OF CONFLICTS OF LAW.

                                      -2-
<PAGE>
 
     IN WITNESS WHEREOF, the Company has caused the signature of its President 
and Secretary to be printed hereon.

                                       EQUALNET HOLDING CORP.


                                       By: _____________________________________
                                                      President


ATTEST:

By: ________________________________
           Secretary

                                      -3-