<PAGE>

THE WARRANT REPRESENTED BY THIS CERTIFICATE AND THE SHARES ISSUABLE UPON 
EXERCISE HEREOF HAVE NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933, AS 
AMENDED (THE "ACT"), OR ANY STATE SECURITIES LAWS AND NEITHER SUCH SECURITIES 
NOR ANY INTEREST THEREIN MAY BE OFFERED, SOLD, PLEDGED, ASSIGNED OR OTHERWISE 
TRANSFERRED UNLESS (1) A REGISTRATION STATEMENT WITH RESPECT THERETO IS 
EFFECTIVE UNDER THE ACT AND ANY APPLICABLE STATE SECURITIES LAWS, OR (2) THE 
COMPANY RECEIVES AN OPINION OF COUNSEL TO THE HOLDER OF SUCH SECURITIES, 
WHICH COUNSEL AND OPINION ARE REASONABLY SATISFACTORY TO THE COMPANY, THAT 
SUCH SECURITIES MAY BE OFFERED, SOLD, PLEDGED, ASSIGNED OR TRANSFERRED IN THE 
MANNER CONTEMPLATED WITHOUT AN EFFECTIVE REGISTRATION STATEMENT UNDER THE ACT 
OR APPLICABLE STATE SECURITIES LAWS.
                                       
                         THE TRANSFER OF THIS WARRANT IS
                         RESTRICTED AS DESCRIBED HEREIN.

                      CITADEL COMPUTER SYSTEMS INCORPORATED

                Warrant for the Purchase of Shares of Common Stock,
                            par value $.01 per share

No. 1                                                             150,000 Shares

    THIS CERTIFIES that, for value received, Worldwide PetroMoly Inc. (the 
"Holder"), is entitled to subscribe for and purchase from Citadel Computer 
Systems Incorporated, a Delaware corporation (the "Company"), upon the terms 
and conditions set forth herein, at any time or from time to time after 
January 12, 1997 until 5:00 P.M. on January 12, 2000, Central time (the 
"Exercise Period"), 150,000 shares of the Common Stock; at an exercise price 
of $0.59 per share (the "Exercise Price").  The number of shares of Common 
Stock issuable upon exercise of the Warrants (collectively, the "Warrant 
Shares") and the Exercise Price may be adjusted from time to time as 
hereinafter set forth.

    1.   EXERCISE.  This Warrant may be exercised at any time during the 
Exercise Period as to the whole or any lesser number of whole Warrant Shares, 
by the surrender of this Warrant (with the election form at the end hereof 
duly executed) to the Company at its office at 3811 Turtle Creek Boulevard, 
Suite 330, Dallas, Texas 75219, or at such other place as the Company may 
designate in writing, together with a check payable to the order of the 
Company in an amount equal to the Exercise Price multiplied by the number of 
Warrant Shares for which this Warrant is being exercised.

    2.   TITLE.  Upon each exercise of the Holder's rights to purchase 
Warrant Shares, the Holder shall be deemed to be the holder of record of the 
Warrant Shares issuable upon such exercise, notwithstanding that the transfer 
books of the Company shall then be closed or 



                                       1
<PAGE>

certificates representing such Warrant Shares shall not then have been 
actually delivered to the Holder.  As soon as practicable after each such 
exercise of this Warrant, the Company shall issue and deliver to the Holder a 
certificate or certificates for the Warrant Shares issuable upon such 
exercise, registered in the name of the Holder or its designee.  If this 
Warrant should be exercised in part only, the Company shall, upon surrender 
of this Warrant for cancellation, execute and deliver a new Warrant 
evidencing the right of the Holder to purchase the balance of the Warrant 
Shares (or portions thereof) subject to purchase hereunder.

    3.   TRANSFER AND RESTRICTIONS ON TRANSFER.  (a) This Warrant and any 
Warrants issued upon the transfer or exercise in part of this Warrant shall 
be numbered and shall be registered in a Warrant Register as they are issued. 
 The Company shall be entitled to treat the registered holder of any Warrant 
on the Warrant Register as the owner in fact thereof for all purposes. The 
Company shall not be bound to recognize any equitable or other claim to or 
interest in such Warrant on the part of any other person.  The Company shall 
not be liable for any registration or transfer of Warrants that are 
registered or to be registered in the name of a fiduciary or the nominee of a 
fiduciary, unless such registration or transfer is made with the Company's 
actual knowledge that a fiduciary or nominee is committing a breach of trust 
in requesting such registration or transfer, or with the knowledge of such 
facts that its participation therein amounts to bad faith.  This Warrant 
shall be transferable only on the books of the Company upon delivery thereof 
duly endorsed by the Holder or by his duly authorized attorney or 
representative, or accompanied by proper evidence of succession, assignment, 
or authority to transfer.  In all cases of transfer by an attorney, executor, 
administrator, guardian, or other legal representative, duly authenticated 
evidence of his or its authority shall be produced.  Upon any registration of 
transfer, the Company shall deliver a new Warrant or Warrants to the person 
entitled thereto.  This Warrant may be exchanged, at the option of the Holder 
thereof, for another Warrant, or other Warrants of different denominations, 
of like tenor and representing in the aggregate the right to purchase a like 
number of Warrant Shares (or portions thereof), upon surrender to the Company 
or its duly authorized agent.  The Company shall have no obligation to cause 
Warrants to be transferred on its books to any person unless such transfer is 
registered under the Securities Act of 1933, as amended (the "Act"), and 
applicable state securities laws or unless the Company receives an opinion of 
counsel to the Holder, which counsel and opinion are reasonably satisfactory 
to the Company, that the Warrant may be transferred in the manner 
contemplated without an effective registration statement under the Act or 
applicable state securities laws.

         (b)  The Holder acknowledges that the Holder has been advised by the 
Company that neither this Warrant nor the Warrant Shares have been registered 
under the Act, that this Warrant is being or has been issued and the Warrant 
Shares may be issued on the basis of the statutory exemption provided by 
Section 4(2) of the Act or Regulation D promulgated thereunder, or both, 
relating to transactions by an issuer not involving any public offering, and 
that the Company's reliance thereon is based in part upon the representations 
made by the original Holder.  The Holder acknowledges that he has been 
informed by the Company of, or is otherwise familiar with, the nature of the 
limitations imposed by the Act and the rules and regulations thereunder on 
the transfer of securities.  In particular, the Holder agrees that no sale, 
assignment or transfer of 



                                       2
<PAGE>

this Warrant or the Warrant Shares shall be valid or effective, and the 
Company shall not be required to give any effect to any such sale, assignment 
or transfer, unless (i) the sale, assignment or transfer of this Warrant or 
such Warrant Shares is registered under the Act, it being understood that the 
Company has no obligation or intention to so register this Warrant or the 
Warrant Shares except as specifically provided herein, or (ii) this Warrant 
or such Warrant Shares are sold, assigned or transferred in accordance with 
all the requirements and limitations of Rule 144 under the Act, it being 
understood that Rule 144 may not be available at the time of the original 
issuance of this Warrant for the sale of this Warrant or the Warrant Shares 
and that there can be no assurance that Rule 144 sales will be available at 
any subsequent time, or (iii) such sale, assignment, or transfer is otherwise 
exempt from registration under the Act.

    4.   ADJUSTMENT OF EXERCISE PRICE AND NUMBER OF WARRANT SHARES.  If the 
Company shall at any time after the date the Warrants were first issued (i) 
declare a dividend on the outstanding Common Stock payable in shares of its 
capital stock, (ii) subdivide the outstanding Common Stock, (iii) combine the 
outstanding Common Stock into a smaller number of shares, (iv) issue any 
shares of its capital stock by reclassification of the Common Stock 
(including any such reclassification in connection with a consolidation or 
merger in which the Company is the continuing corporation), or (v) make any 
distribution of its assets to holders of its Common Stock as a liquidation or 
partial liquidation dividend or by way of return of capital; then, in each 
case, the Exercise Price, and the number of Warrant Shares in effect at the 
time of the record date for such dividend or of the effective date of such 
subdivision, combination, or reclassification, shall be proportionately 
adjusted so that the Holder after such time shall be entitled to receive the 
aggregate number and kind of shares which, if such Warrant had been exercised 
immediately prior to such time, the Holder would have owned upon such 
exercise and been entitled to receive by virtue of such dividend, 
subdivision, combination, or reclassification.  Such adjustment shall be made 
successively whenever any event listed above shall occur.

    5.   MERGER.  (a)  In case of any consolidation with or merger of the 
Company with or into another corporation (other than a merger or 
consolidation in which the Company is the surviving or continuing 
corporation), or in case of any sale, lease, or conveyance to another 
corporation of the property and assets of any nature of the Company as an 
entirety or substantially as an entirety, such successor, or such leasing or 
purchasing corporation, as the case may be, shall (i) execute with the Holder 
an agreement providing that the Holder shall have the right thereafter to 
receive upon exercise of this Warrant solely the kind and amount of shares of 
stock and other securities, property, cash, or any combination thereof 
receivable upon such consolidation, merger, sale, lease, or conveyance by a 
holder of the number of shares of Common Stock for which this Warrant might 
have been exercised immediately prior to such consolidation, merger, sale, 
lease, or conveyance and (ii) make effective provision in its certificate of 
incorporation or otherwise, if necessary, to effect such agreement.  Such 
agreement shall provide for adjustments which shall be as nearly equivalent 
as practicable to the adjustments in Section 4.

         (b)  In case of any reclassification or change of the shares of 
Common Stock issuable upon exercise of this Warrant (other than a change in 
par value or as a result of a subdivision or combination, but including any 
change in the shares into two or more classes or 



                                       3
<PAGE>

series of shares), or in case of any consolidation or merger of another 
corporation into the Company in which the Company is the continuing 
corporation and in which there is a reclassification or change (including a 
change to the right to receive cash or other property, including, without 
limitation, a reverse subsidiary merger) of the shares of Common Stock (other 
than a change in par value, or as a result of a subdivision or combination, 
but including any change in the shares into two or more classes or series of 
shares), the Holder shall have the right thereafter to receive upon exercise 
of this Warrant solely the kind and amount of shares of stock and other 
securities, property, cash, or any combination thereof receivable upon such 
reclassification, change, consolidation, or merger by a holder of the number 
of shares of Common Stock for which this Warrant might have been exercised 
immediately prior to such reclassification, change, consolidation, or merger. 
Thereafter, appropriate provision shall be made for adjustments which shall 
be as nearly equivalent as practicable to the adjustments in Section 4.

         (c)  The above provisions of this Section 5 shall similarly apply to 
successive reclassifications and changes of shares of Common Stock and to 
successive consolidations, mergers, sales, leases, or conveyances.

    6.   COVENANTS OF COMPANY.  

         (a)  The Company shall at all times reserve and keep available out 
of its authorized and unissued Common Stock, solely for the purpose of 
providing for the exercise of the rights to purchase all Warrant Shares 
granted pursuant to the Warrants, such number of shares of Common Stock as 
shall, from time to time, be sufficient therefor.  The Company covenants that 
all shares of Common Stock issuable upon exercise of this Warrant, upon 
receipt by the Company of the full Exercise Price therefor, shall be validly 
issued, fully paid, nonassessable, and free of preemptive rights.

         (b)  If at any time the Company shall propose to:

              i)  pay any dividend or make any distribution on shares of 
Common Stock in shares of Common Stock or make any other distribution (other 
than regularly scheduled cash dividends which are not in a greater amount per 
share than the most recent such cash dividend) to all holders of Common 
Stock; or

              ii)  issue any rights, warrants, or other securities to all 
holders of Common Stock entitling them to purchase any additional shares of 
Common Stock or any other rights, warrants, or other securities; or

              iii)  effect any reclassification or change of outstanding 
shares of Common Stock, or any consolidation, merger, sale, lease, or 
conveyance of property, described in Section 5; or

              iv)  effect any liquidation, dissolution, or winding-up of the 
Company; or



                                       4
<PAGE>

              v)  take any other action which would cause an adjustment to 
the Exercise Price;

then, and in any one or more of such cases, the Company shall give written 
notice thereof, by registered mail, postage prepaid, to the Holder at the 
Holder's address as it shall appear in the Warrant Register, mailed at least 
15 days prior to (i) the date as of which the holders of record of shares of 
Common Stock to be entitled to receive any such dividend, distribution, 
rights, warrants, or other securities are to be determined, (ii) the date on 
which any such reclassification, change of outstanding shares of Common 
Stock, consolidation, merger, sale, lease, conveyance of property, 
liquidation, dissolution, or winding-up is expected to become effective, and 
the date as of which it is expected that holders of record of shares of 
Common Stock shall be entitled to exchange their shares for securities or 
other property, if any, deliverable upon such reclassification, change of 
outstanding shares, consolidation, merger, sale, lease, conveyance of 
property, liquidation, dissolution, or winding-up, or (iii) the date of such 
action which would require an adjustment to the Exercise Price.

    7.   EXPENSES OF EXERCISE.  The issuance of any shares or other 
securities upon the exercise of this Warrant, and the delivery of 
certificates or other instruments representing such shares or other 
securities, shall be made without charge to the Holder for any tax or other 
charge in respect of such issuance. The Company shall not, however, be 
required to pay any tax which may be payable in respect of any transfer 
involved in the issue and delivery of any certificate in a name other than 
that of the Holder and the Company shall not be required to issue or deliver 
any such certificate unless and until the person or persons requesting the 
issue thereof shall have paid to the Company the amount of such tax or shall 
have established to the satisfaction of the Company that such tax has been 
paid.

    8.   REGISTRATION OF WARRANT SHARES.

         (a)  Upon the request of the Holder, the Company shall file a 
registration statement with the Commission pursuant to which the Company will 
register or qualify the Registrable Securities to the extent requisite to 
permit the public offering and sale of the Registrable Securities and will 
use its best efforts to cause such registration statement to become effective 
as promptly as practicable for one half of the Registrable Securities as of a 
date six months, and for the remaining half of such Registrable Securities as 
of a date nine months, following a public offering of Company shares pursuant 
to a registration statement on a form other than Form S-8 or Form S-4.  
Notwithstanding the foregoing, the Company shall in no event be required to 
keep any such registration or qualification in effect for a period in excess 
of two years from the date on which the Holders are first free to sell such 
Registrable Securities.

         (b)  In connection with registration of securities pursuant to this 
Section 8, the Holder shall pay all fees and expenses with respect to its 
shares, including broker/dealer commissions, underwriting discounts, the 
expenses of such underwriter, fees and disbursements of counsel of such 
Holder and any stock transfer taxes incurred with respect of the Registrable 
Securities of such Holder.  The Company shall bear all other expenses 
incurred in connection with such Registration Statement. 



                                       5
<PAGE>

      9. STOP TRANSFER LEGEND. Unless registered pursuant to Act, the Warrant 
Shares issued upon exercise of the Warrants shall be subject to a stop 
transfer order and the certificate or certificates evidencing such Warrant 
Shares shall bear the following legend:

         "THE SHARES REPRESENTED BY THIS CERTIFICATE HAVE NOT BEEN REGISTERED 
     UNDER THE SECURITIES ACT OF 1933, AS AMENDED (THE "ACT"), OR ANY STATE 
     SECURITIES LAWS AND NEITHER SUCH SECURITIES NOR ANY INTEREST THEREIN MAY 
     BE OFFERED, SOLD, PLEDGED, ASSIGNED OR OTHERWISE TRANSFERRED UNLESS 
     (1) A REGISTRATION STATEMENT WITH RESPECT THERETO IS EFFECTIVE UNDER THE 
     ACT AND ANY APPLICABLE STATE SECURITIES LAWS, OR (2) THE COMPANY RECEIVES 
     AN OPINION OF COUNSEL TO THE HOLDER OF SUCH SECURITIES, WHICH COUNSEL AND 
     OPINION ARE REASONABLY SATISFACTORY TO THE COMPANY, THAT SUCH SECURITIES 
     MAY BE OFFERED, SOLD, PLEDGED, ASSIGNED OR TRANSFERRED IN THE MANNER 
     CONTEMPLATED WITHOUT AN EFFECTIVE REGISTRATION STATEMENT UNDER THE ACT 
     OR APPLICABLE STATE SECURITIES LAWS."

     10. REPLACEMENT OF WARRANT.  Upon receipt of evidence satisfactory to 
the Company of the loss, theft, destruction, or mutilation of any Warrant and 
(i) in the case of any such loss, theft or destruction upon delivery of 
indemnity satisfactory to the Company in form and amount or, (ii) in the case 
of any such mutilation upon surrender of such warrant for cancellation of the 
principal office of the Company, upon reimbursement of the Company's 
reasonable incidental expenses, the Company shall execute and deliver to the 
Holder thereof a new Warrant of like date, tenor, and denomination.

     11. NO RIGHTS AS STOCKHOLDER.  The Holder of any Warrant shall not have 
solely on account of such status, any rights of a stockholder of the Company, 
either at law or in equity, or to any notice of meetings of stockholders or 
of any other proceedings of the Company, except as provided in this Warrant.

     12. CHOICE OF LAW.  This Warrant has been negotiated and consummated in 
the State of Texas and shall be construed in accordance with the laws of the 
State of Texas applicable to contracts made and performed within such State, 
without regard to principles governing conflicts of law.

     13. JURISDICTION.  The Company irrevocably consents to the jurisdiction 
of the courts of the State of Texas and of any federal court located in such 
State in connection with any action or proceeding arising out of or relating 
to this Warrant, any document or instrument delivered pursuant to, in 
connection with or simultaneously with this Warrant, or a breach of this 
Warrant or any such document or instrument.  Within 30 days after such 
service, or such other time as may be mutually agreed upon in writing by the 
attorneys for the parties to such action or 



                                       6
<PAGE>

proceeding, the Company shall appear to answer such summons, complaint or 
other process.  Should the Company so served fail to appear or answer within 
such 30-day period or such extended period, as the case may be, the Company 
shall be deemed in default and judgment may be entered against the Company 
for the amount as demanded in any summons, complaint or other process so 
served.

     14. SEVERABILITY.  Any provision contained in this Warrant which is 
prohibited or unenforceable by law shall be ineffective to the extent of such 
prohibition or unenforceability without invalidating the remaining provisions 
contained in this Warrant.

     15. HEADINGS.  The descriptive headings of the several Sections of this 
Warrant are inserted for convenience only and do not constitute part of the 
Warrant.

Dated:  December 12, 1996.


                                  CITADEL COMPUTER SYSTEMS INCORPORATED


                                  By: /s/ GEORGE SHARP
                                      -------------------------------------
                                      George Sharp, Chief Executive Officer










                                       7
<PAGE>

To:  Citadel Computer Systems Incorporated
     3811 Turtle Creek Boulevard
     Suite 330
     Dallas, Texas  75219
                                       
                              ELECTION TO EXERCISE

    The undersigned hereby exercises his or its rights to purchase 
___________ Warrant Shares covered by the within Warrant and tenders payment 
herewith in the amount of $___________ in accordance with the terms thereof, 
and requests that certificates for such securities be issued in the name of, 
and delivered to:


--------------------------------------------------------------------------------

--------------------------------------------------------------------------------

--------------------------------------------------------------------------------
                   (Print Name, Address and Social Security
                        or Tax Identification Number)

and, if such number of Warrant Shares shall not be all the Warrant Shares 
covered by the within Warrant, that a new Warrant for the balance of the 
Warrant Shares covered by the within Warrant be registered in the name of, 
and delivered to, the undersigned at the address stated below.

Dated:                  
      ------------------

Name:
     ---------------------------------------------------------------------------
                                      (Print)

Address: 
        ------------------------------------------------------------------------


                                       -----------------------------------------
                                                     (Signature)



                                       8