<PAGE>   1
                                                                     EXHIBIT 2.3


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                               PURCHASE AGREEMENT

                                     BETWEEN

                              OMNIPOINT CORPORATION
                                    (SELLER)

                                       AND

                         COOK INLET/VS GSM III PCS, LLC
                                   (PURCHASER)


                            DATED AS OF JUNE 23, 1999


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<PAGE>   2
               PURCHASE AGREEMENT, dated as of June 23, 1999, by and between
Omnipoint Corporation, a Delaware corporation, on its own behalf and on behalf
of each of its wholly owned Subsidiaries (hereinafter collectively referred to
as "Seller"), and Cook Inlet/VS GSM III PCS, LLC, a Delaware limited liability
company ("Purchaser").

               WHEREAS, Seller wishes to sell, assign and transfer to Purchaser
certain of Seller's licenses, interests, and other rights owned by Seller in
exchange for membership interests in Purchaser, upon the terms and subject to
the conditions set forth in this Agreement; and

               WHEREAS, concurrently herewith Seller and VoiceStream Wireless
Corporation ("VoiceStream") are entering into an Agreement and Plan of
Reorganization (the "Reorganization Agreement"), pursuant to which, among other
things, wholly owned subsidiaries of VoiceStream Wireless Holding Corporation, a
Delaware corporation, will be merged with and into each of Seller and
VoiceStream; and

               WHEREAS, the consummation of the closing under the Reorganization
Agreement is conditioned upon the consummation of the Closing under this
Agreement, and the consummation of the Closing under this Agreement is
conditioned upon the satisfaction or waiver of all conditions set forth in
Article 9 of the Reorganization Agreement.

               NOW, THEREFORE, in consideration of the premises and the
respective agreements herein set forth, the parties hereto agree as follows:


                                    ARTICLE 1

                                  Defined Terms

        1.1 (a) Defined Terms. The following terms, as used herein, have the
following meanings:

               "Affiliate" means, with respect to any Person, any other Person
directly or indirectly controlling, controlled by, or under common control with
such Person provided that, for purposes of this definition, "control"
(including, with correlative meanings, the terms "controlled by" and "under
common control with"), as used with respect to any Person, shall mean the
possession, directly or indirectly, of the power to direct or cause the
direction of the management and policies of such Person, whether through the
ownership of voting securities or by contract or otherwise.

               "Assets" means all of the Licenses, permits and franchises
(governmental or otherwise) (other than the FCC Licenses), fixed assets,
equipment, Transmission Equipment, assets, properties, interests, maintenance
and/or service agreements, business,


<PAGE>   3
good will, claims and other rights of Seller of every kind and nature
whatsoever, tangible or intangible, vested or unvested, contingent or otherwise,
real, personal or mixed, and wherever located, whether or not reflected on the
books and records of Seller and whether or not described herein or in any of the
schedules delivered or to be delivered to Purchaser hereunder, including, but
not limited to, Tangible Personal Property, rights under Contracts (including
security deposits thereunder), Receivables, Inventories, Intellectual Property
Rights, investments, Warranties, Records, prepaid expenses and advances, but in
any case excluding the Excluded Assets.

               "Assumed Liabilities" shall have the meaning specified in Section
3.1 hereof.

               "Assumption Agreement" shall have the meaning specified in
Section 3.3 hereof.

               "BTA" means Basic Trading Area as designated by the FCC.

               "Bill of Sale" shall have the meaning specified in Section 3.4
hereof.

               "Business Day" means a day other than a Saturday, Sunday or other
day on which commercial banks in New York City, Seattle, Washington or
Anchorage, Alaska are authorized or required by law to close.

               "Communications Act" means the Communications Act of 1934 and the
Telecommunications Act of 1996 (together with the rules, regulations and
published decisions of the FCC).

               "Contracts" means leases (whether for real or personal property),
rental agreements, sales and purchase orders, acknowledgments, agreements,
permits, maintenance and service contracts, commitments and any and all other
contracts or binding arrangements, whether written or oral, express or implied.

               "Delaware Law" means the Delaware General Corporation Law.

               "Excluded Assets" means all Assets of Seller not being sold,
assigned or transferred to Purchaser pursuant to Section 2.1.

               "FAA" means the Federal Aviation Administration and any successor
agency or body.

               "FCC" means the Federal Communications Commission and any
successor agency or body.


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<PAGE>   4
               "FCC Applications" means all appropriate applications for FCC
approval, and such other documents as may be required, with respect to the
transfer of the FCC Licenses from Seller to Purchaser contemplated herein.

               "FCC Consent" means an order of the FCC, or by the staff of the
FCC acting pursuant to delegated authority, granting its consent to the
applications referred to in Section 8.1(b) of this Agreement required to permit
the consummation of the transactions contemplated by this Agreement.

               "FCC Consent Date" means the date on which Public Notice is given
of the FCC Consent pursuant to the Rule s and regulations of the FCC.

               "FCC Licenses" means the licenses or applications therefor and
awards related thereto ("Licenses") issued by the FCC to provide radio
telecommunications services using either 15 MHz or 30 MHz of spectrum in the 30
MHz band of spectrum in the "C" block (1895- 1910 MHz/1975-1990 MHz) and the 10
MHz band of spectrum in the "F" block (1890- 1895 MHz /1970-1975 MHz) in various
BTAs.

               "Final Order" means an action or decision that has been granted
by the FCC as to which (i) no request for a stay or similar request is pending,
no stay is in effect, the action or decision has not been vacated, reversed, set
aside, annulled or suspended and any deadline for filing such request that may
be designated by statute or regulation has passed, (ii) no petition for
rehearing or reconsideration or application for review is pending and the time
for the filing of any such petition or application has passed, (iii) the FCC
does not have the action or decision under reconsideration on its own motion and
the time within which it may effect such reconsideration has passed and (iv) no
appeal is pending, including other administrative or judicial review, or in
effect and any deadline for filing any such appeal that may be designated by
statute or rule has passed.

               "Governmental Body" means any domestic or foreign national,
state, multi-state or municipal or other local government, any subdivision,
agency, commission or authority thereof, any court, or any quasi-governmental or
private body exercising any regulatory or taxing authority thereunder.

               "Governmental Consents" means all authorizations, consents,
approvals, exceptions or other actions by Governmental Bodies required to
consummate the transactions contemplated hereby.

               "Group" means "group," as such term is defined in Rule 13d-3 of
the 1934 Act.

               "HSR Act" means the Hart-Scott-Rodino Antitrust Improvements Act
of 1976.


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<PAGE>   5
               "Indebtedness" of any Person at any date means: (a) all
indebtedness of such Person for borrowed money or for the deferred purchase
price of property or services (other than current trade liabilities incurred in
the ordinary course of business and payable in accordance with customary
practices), (b) any other indebtedness of such Person which is evidenced by a
note, bond, debenture or similar instrument, (c) all obligations of such Person
under financing leases, (d) all obligations of such Person in respect of
acceptances issued or created for the account of such Person and with respect to
unpaid reimbursement obligations related to letters of credit issued for the
account of such Person and (e) all liabilities secured by any Lien on any
property owned by such Person even though such Person has not assumed or
otherwise become liable for the payment thereof.

               "Intellectual Property Rights" means (i) Patents, (ii) Know-how,
(iii) Trademarks, (iv) Trade Names, and (v) shop rights, copyrights, inventions,
service marks and all other intellectual property rights, whether registered or
not.

               "Inventories" means all inventory and supplies, including,
without limitation, inventories of materials, spare parts, work-in-process and
finished goods.

               "Know-how" means all trade secrets, know-how (including, without
limitation, product know-how and use and application know-how), process, product
designs, specifications, quality control procedures, manufacturing, engineering
and other drawings, computer databases and software, telephone numbers,
facsimile numbers, technology and all other information and intangibles,
including, without limitation, technical information, safety information,
engineering data and design and engineering specifications, research records,
market surveys and all promotional literature, subscriber, customer and supplier
lists and similar data.

               "knowledge" means, with respect to any fact, the conscious
awareness of such fact by an executive officer (as defined under the 1933 Act)
of the relevant Person.

               "Licenses" means all local, municipal, state and federal
licenses, franchises, permits, certificates, consents, approvals, waivers,
rights and authorizations used or required for use in connection with the
utilization of, or business conducted in, the areas covered by the FCC Licenses
of Seller being transferred to Purchaser hereunder.

               "Lien" as to any Person, means any mortgage, lien, pledge,
adverse claim, charge, security interest or other encumbrance (including,
without limitation rights of first refusal, proxy rights and other similar
rights) in or on, or any interest or title of any vendor, lessor, lender or
other secured party to or of such Person under any conditional sale or other
title retention agreement or capital lease with respect to, any property or
asset owned or held by such Person, or the signing or filing of a financing
statement


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<PAGE>   6
which names such Person as debtor, or the signing of any security agreement
authorizing any other party as the secured party thereunder to file any
financing statement.

               "LLC Agreement" means the Limited Liability Company Agreement of
Purchaser, which shall be amended to be in the form set forth in Exhibit A
hereto immediately prior to the Closing.

               "1933 Act" means the Securities Act of 1933.

               "1934 Act" means the Securities Exchange Act of 1934.

               "Order" means and includes any order, writ, injunction, decree,
judgment, award, determination or written direction of any court, arbitrator or
Governmental Body.

               "Patents" means patents (including all reissues, divisions,
continuations, continuations in part and extensions thereof), patent
applications and patent disclosures docketed and all other patents rights
(including, without limitation, all claims against third parties for past
infringement not heretofore asserted).

               "Permitted Liens" means Easements, rights of way or similar
encumbrances on real property which are in the ordinary course and which do not
materially affect the value, use and insurability of title of such real
property.

               "Person" means an individual, corporation, partnership, limited
liability company, association, trust or other entity or organization, including
a government or political subdivision or an agency or instrumentality thereof.

               "Purchaser Material Adverse Effect" means a material adverse
effect on the business, financial condition, prospects, assets or results of
operations of Purchaser taken as a whole, excluding any such effect resulting
from or arising in connection with (A) this Agreement, the transactions
contemplated hereby or the announcement thereof, (B) changes or conditions
generally affecting the industries in which Purchaser operates or (C) changes in
general economic, regulatory or political conditions. For the purposes of
Sections 9.1(c) and 9.1(e), Item A of the previous sentence shall not be
excluded from the definition of Purchaser Material Adverse Effect.

               "Receivables" shall mean all accounts receivable, claims, notes
and other amounts receivable by Seller or which may be claimed by Seller as a
result of Seller's business or operations or ownership of the Assets, including,
without limitation, all amounts due from customers, subscribers, vendors and
employees, together with any unpaid financing charges accrued thereon, whether
or not arising in the ordinary course of business, including the proceeds of all
of the foregoing received after the date hereof.


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<PAGE>   7
               "Records" shall mean originals, or, to the extent originals are
not available, true and complete copies of all business, accounting and
financial records (excluding corporate minute books and records), property
records, contract records, personnel records, correspondence, files, books and
documents of Seller, including, without limitation, sales, marketing and
advertising data and materials, customer and subscriber lists, mailing lists of
any and all types, vendor and customer invoices, billing records, software and
related documentation, artwork, photographs and advertising material, manuals
and teaching aids, and all other records relating to the business of Seller as
presently or heretofore conducted.

               "Retained Liabilities" shall have the meaning specified in
Section 3.2 hereof.

               "SEC" means the Securities and Exchange Commission and any
successor agency or body.

               "Seller Group" means Seller and Seller Subsidiaries.

               "Seller Material Adverse Effect" means a material adverse effect
on the business, financial condition, prospects, assets or results of operations
of Seller Group taken as a whole, excluding any such effect resulting from or
arising in connection with (A) this Agreement, the transactions contemplated
hereby or the announcement thereof, (B) changes or conditions generally
affecting the industries in which Seller Group operates or (C) changes in
general economic, regulatory or political conditions. For the purposes of
Sections 9.1(c) and 9.1(e), Item A of the previous sentence shall not be
excluded from the definition of Seller Material Adverse Effect.

               "Seller Subsidiary" means a Subsidiary of Seller.

               "Subsidiary" means, with respect to any Person, any entity of
which securities or other ownership interests having ordinary voting power to
elect a majority of the board of directors or other persons performing similar
functions are at any time directly or indirectly owned by such Person.

               "Tangible Personal Property" means all fixed assets, machinery,
equipment, Transmission Equipment, tools, vehicles, furniture, fixtures,
leasehold improvements, office equipment, plant, inventory (including, without
limitation, Inventories) and other tangible personal property owned by Seller.

               "Trademarks" means trademarks, registrations thereof, pending
applications therefor and such unregistered rights as may exist through use.


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<PAGE>   8
               "Trade Names" means trade names, band marks, trade dress, brand
names and all other names and slogans embodying Seller's good will for which no
trademark registration has been obtained and for which no application is
pending.

               "Transmission Equipment" means all cell site towers, fixtures and
equipment, microwave towers, fixtures and equipment, transmitting or receiving
equipment, antennae, hardware, software, and ancillary and related equipment and
facilities used to provide broadband PCS, whether under the GSM standard or
otherwise, and to deliver voice, data and related electronic signals between or
among cell sites and/or between or among cell sites and the associated switch
constituting the interconnection to the landline public switched telephone
network.

               "Warranties" means all warranties in favor of Seller with respect
to any and all equipment, Transmission Equipment or other personal property
heretofore or hereafter sold to Seller and being transferred to Purchaser
hereunder.

               Any reference in this Agreement to a statute shall be to such
statute, as amended from time to time, and to the rules and regulations
promulgated thereunder.

               (b) Each of the following terms is defined in the Section set
forth opposite such term:


<TABLE>
<CAPTION>
<S>                                                <C>
Assumed Liabilities                                     3.1
Assumption Agreement                                    3.3
Closing Date                                        2.3.(a)
Closing                                                 2.3(a)
Due Date                                               7(b)
Purchased Membership Interests                          2.1(a)
Purchaser                                          Preamble
Reorganization Agreement                           Preamble
Schedule I Assets                                       2.2(a)
Schedule 3.1(a) (Schedule I Assumed Liabilities)        3.1
Seller                                             Preamble
VoiceStream Agreement                                  7(a)
VoiceStream Wireless Corporation                   Preamble
</TABLE>


               (c) All defined terms used herein but not otherwise defined
herein shall have the meanings ascribed to them in the Reorganization Agreement.

               (d) Unless the context otherwise requires, the terms defined in
this Article 1 or elsewhere in this Agreement shall have the meanings herein
specified for all purposes of this Agreement, applicable to both the singular
and plural forms of any of the terms defined herein. When a reference is made in
this Agreement to a Section, such


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<PAGE>   9
reference shall be to a Section of this Agreement unless otherwise indicated.
Whenever the words "include," "includes" or "including" are used in this
Agreement, they shall be deemed to be followed by the words "without
limitation." The use of any gender herein shall be deemed to include the neuter,
masculine and feminine genders wherever necessary or appropriate.


                                    ARTICLE 2

                                    Purchase

        2.1 Purchase and Sale. Upon the terms and subject to the conditions set
forth in this Agreement, Seller hereby agrees to sell, assign, transfer, convey
and deliver to Purchaser, and Purchaser hereby agrees to purchase and accept
from Seller all right, title and interest of Seller in and to the following,
free and clear of any and all Liens, subject to the Assumed Liabilities
described in Section 3.1.

               (a) The FCC Licenses listed and/or described on Schedule I (the
"Schedule I Assets").

        2.2 Purchase Price. Upon the terms and subject to the conditions set
forth in this Agreement and in consideration for the sale and/or transfer of the
FCC Licenses set forth in Section 2.1 and the assumption of the Assumed
Liabilities as set forth in Section 3.1, Purchaser hereby agrees to issue,
transfer, convey and deliver to Seller, and Seller hereby agrees to accept from
Purchaser, all of the Class B membership interests in Purchaser which shall
entitle Seller to a Percentage (as defined in the LLC Agreement) of 49.9%, and
an initial Capital Account (as defined in the LLC Agreement) of $21.4 million
(the "Purchased Membership Interests").

        2.3 Closing.

               (a) Closing Date. Consummation of the transactions contemplated
hereby (the "Closing") shall take place, subject to the satisfaction (or express
written waiver) of all conditions to the Closing under Article 9 hereof,
immediately prior to the Closing of the Transactions contemplated by the
Reorganization Agreement. The date on which the Closing takes place shall be
referred to herein as the "Closing Date."

               (b) Location. The Closing shall take place at 11:00 A.M. on the
Closing Date, at the offices of Friedman Kaplan & Seiler LLP located at 875
Third Avenue, New York, New York 10022 or at such other place as the parties
hereto shall agree. At the Closing, the Purchaser shall, upon receipt of
assignment of the FCC Licenses and delivery of the Assets to Purchaser, issue to
Seller the Purchased


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<PAGE>   10
Membership Interests and Seller and Purchaser shall execute the LLC Agreement
substantially in the form attached hereto as Exhibit A.

        2.4 Bill of Sale. At the Closing, Seller shall execute and deliver one
or more bills of sale ("Bill of Sale") and assignments evidencing the sale,
transfer and assignment of the Assets and FCC Licenses to Purchaser.


                                    ARTICLE 3

                        Assumption of Certain Liabilities

        3.1 Assumed Liabilities. As further consideration for the purchase by
Purchaser of the FCC Licenses being purchased hereunder, Purchaser shall assume
and agree to indemnify and hold harmless Seller from and against the obligations
and liabilities of Seller listed and/or described on Schedules 3.1(a) ("Schedule
I Assumed Liabilities"), (herein referred to as the "Assumed Liabilities");
provided that such Assumed Liabilities shall not exceed the amount that, after
netting such Assumed Liabilities against the actual price paid or to be paid to
the FCC (approximately $45 million ) for the FCC Licenses, would cause the value
of the FCC Licenses to equal, in the aggregate, not less than $21.4 million;
provided further that all such Assumed Liabilities shall consist of unsecured
debt to an Affiliate of Seller; and provided further that Seller shall
contribute cash to Purchaser in an amount equal to any amounts payable to the
FCC with respect to any FCC Licenses that remain to be issued as of the Closing
Date.

        3.2 Liabilities Not Assumed. Except for the assumption of the Assumed
Liabilities, Purchaser shall not be obligated to pay or perform or otherwise be
responsible for any liabilities, claims, obligations, judgments, orders, duties
or responsibilities of any kind or nature whatsoever, of Seller or of the
business of Seller or any of its Affiliates, whether arising before, on or after
the date hereof, including, but not limited to, any liabilities or obligations
of Seller arising out of this Agreement and any other liabilities or obligations
of Seller arising before, on or after the Closing Date (collectively the
"Retained Liabilities"). Seller hereby agrees to indemnify and hold harmless
Purchaser from all of the Retained Liabilities.

        3.3 Assumption Agreement. At the Closing Purchaser shall execute and
deliver an assumption agreement in form and substance satisfactory to Seller and
Purchaser (the "Assumption Agreement") and such other instruments in form and
substance reasonably satisfactory to Seller and Purchaser in order to evidence
Purchaser's assumption of the Assumed Liabilities.


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<PAGE>   11
                                    ARTICLE 4

                    Representations and Warranties of Seller

               (a) Seller represents and warrants to Purchaser that all
representations and warranties made by Seller (referred to as Omnipoint in the
Reorganization Agreement) in Article 4 of the Reorganization Agreement are
incorporated herein by reference to the same extent as if fully set forth
herein; provided that for purposes of Article 4 of this Agreement (i) the term
"Agreement" shall also include this Agreement and the term "Transactions" shall
also include the transactions contemplated by this Agreement, (ii) all those
representations and warranties that relate to corporate or governmental
authorization and non-contravention of other agreements shall also be deemed to
refer this Agreement and the transactions contemplated hereby, and (iii) the
term "Seller" shall be deemed to refer to Seller and each of its wholly owned
Subsidiaries.

               (b) Seller represents and warrants to Purchaser that the FCC
Licenses being sold, assigned and transferred to Purchaser hereunder and the
Assumed Liabilities are all of the FCC Licenses and liabilities associated with
the C and F block FCC Licenses owned by Seller (other than those being sold,
assigned and transferred to Cook Inlet/VS GSM II PCS, LLC).


                                    ARTICLE 5

                   Representations and Warranties of Purchaser

        Purchaser represents and warrants to Seller as follows:

        5.1 Existence and Power. Purchaser is a limited liability company duly
organized, validly existing and in good standing under Delaware Law and has all
company power and authority required to carry on its business as now conducted
and to own, operate and lease its property. Purchaser, has heretofore delivered
or made available to Seller a true and complete copy of its limited liability
company agreement as currently in effect.

        5.2 Corporate Authorization.

               (a) The execution, delivery and performance by Purchaser of this
Agreement and the consummation by Purchaser of the transactions contemplated
hereby are within Purchaser's powers and have been duly authorized by all
necessary action on the part of Purchaser. This Agreement has been duly and
validly executed and delivered by Purchaser and, assuming the due and valid
authorization, execution and delivery of this


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<PAGE>   12
Agreement by Seller, constitutes a valid and binding agreement of Purchaser,
enforceable against it in accordance with its terms except as may be limited by
bankruptcy, insolvency, reorganization, moratorium and other similar laws
affecting creditors' rights generally and by equitable principles of general
applicability.

               (b) Purchaser has (i) determined that this Agreement and the
transactions contemplated hereby are advisable and fair to it and in its best
interest; and (ii) approved this Agreement and the transactions contemplated
hereby. No other proceedings on the part of Purchaser are necessary to authorize
or approve this Agreement or to consummate the transactions contemplated hereby.

        5.3 Governmental Authorization.

               (a) The execution, delivery and performance by Purchaser of this
Agreement and the consummation by Purchaser of the transactions contemplated
hereby require no action by or in respect of, or filing with, any Governmental
Body, other than: (i) compliance with any applicable requirements of the
Communications Act; (ii) compliance with any applicable requirements of the HSR
Act; (iii) compliance with FAA regulations; (iv) compliance with any applicable
requirements of state and local public utility commissions or similar entities;
and (v) any actions or filing, the absence of which would not in the aggregate
prevent or delay consummation of the transactions contemplated hereby in any
material respect, or otherwise prevent Purchaser from performing its obligations
under this Agreement in any material respect.

               (b) Purchaser has not made any misstatements of fact, or omitted
to disclose any fact, to any Governmental Body, which misstatements or
omissions, individually or in the aggregate, could subject any Licenses or
authorizations to revocation or failure to renew.

        5.4 Non-contravention. The execution, delivery and performance by
Purchaser of this Agreement and the consummation by Purchaser of the
transactions contemplated hereby do not and will not (i) contravene, conflict
with, or result in any violation or breach of any provision of the limited
liability company agreement or other governing instrument of Purchaser (ii)
assuming compliance with the matters referred to in Section 5.3, contravene,
conflict with or result in a violation or breach of any provision of any
applicable law, statute, ordinance, rule, regulation, judgment, injunction,
order, or decree; (iii) require any consent or other action by any Person under,
constitute a default (or an event that, with or without notice or lapse of time
or both, would constitute a default) under, or cause or permit the termination,
cancellation, acceleration, triggering or other change of any right or
obligation or the loss of any benefit to which Purchaser is entitled under (A)
any provision of any agreement or other instrument binding upon Purchaser or (B)
any License, franchise, permit, certificate, approval or other similar
authorization held by, or affecting, or relating in any way to, the assets or
business of, Purchaser; or


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<PAGE>   13
(iv) result in the creation or imposition of any Lien on any asset of Purchaser,
other than such exceptions in the case of clauses (ii), (iii) and (iv) as would
not be, individually or in the aggregate, reasonably expected to have a
Purchaser Material Adverse Effect or materially impair or delay the ability of
Purchaser to consummate the transactions contemplated hereby.

        5.5 Capitalization.

               (a) Except for the obligations to Seller hereunder, and any
issuances of membership interests to Purchaser's sole member, there are no
outstanding subscriptions, options, warrants, rights or convertible or
exchangeable securities issued by Purchaser or other agreements or commitments
to which Purchaser is a party of any character relating to the issued or
unissued membership interests or other securities of Purchaser, including any
agreement or commitment obligating Purchaser to issue, deliver or sell, or cause
to be issued, delivered or sold, membership interests or other securities of
Purchaser, to grant, extend or enter into any subscription, option, warrant,
right or convertible or exchangeable security or other similar agreement or
commitment with respect to Purchaser or to make any payments pursuant to any
stock based or stock related plan or award.

        5.6 Finders' Fees. There is no investment banker, broker, finder or
other intermediary that has been retained by or is authorized to act on behalf
of Purchaser who might be entitled to any fee or commission from Purchaser in
connection with the transactions contemplated by this Agreement other than as
specified in the Reorganization Agreement.

        5.7 Formation and Liabilities. Purchaser was formed on June 21, 1999 for
purposes of consummating the transactions contemplated hereby. Other than in
connection with the transactions contemplated by this Agreement, Purchaser has
taken no actions, incurred no liabilities and conducted no business.


                                    ARTICLE 6

                               Covenants of Seller

        The covenants of Seller (referred to as Omnipoint in the Reorganization
Agreement) set forth in Article 6 of the Reorganization Agreement are hereby
incorporated herein by reference for the benefit of Purchaser to the same extent
as if fully set forth herein; provided, that for purposes of Article 6 of this
Agreement, the term "VoiceStream" shall be deemed to refer to Purchaser.


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<PAGE>   14
                                    ARTICLE 7

                             Covenants of Purchaser

        Purchaser agrees that during the period from the date hereof until the
Closing Date it shall not take any action, conduct any business, acquire any
assets, incur any liabilities or enter into any Contracts (other than the LLC
Agreement or as contemplated by the agreement of even date herewith between Cook
Inlet GSM, Inc. and VoiceStream (the "VoiceStream Agreement")), except in
connection with or in furtherance of the transactions contemplated hereby.


                                    ARTICLE 8

                        Covenants of Seller and Purchaser

            Each of the parties hereto agree that:

        8.1 Best Efforts.

               (a) Subject to the terms and conditions of this Agreement, each
of the parties will use its reasonable best efforts to, and Seller will
cooperate with and assist Purchaser, and with respect to matters that are within
Seller's power or control will use its best efforts to promptly (i) take, or
cause to be taken, all actions and to do, or cause to be done, all things
necessary, proper or advisable under applicable laws and regulations to
consummate the transactions contemplated by this Agreement as soon as
practicable, including preparing and filing as promptly as practicable all
documentation to effect all necessary filings, notices, petitions, statements,
registrations, submissions of information, applications and other documents, and
(ii) obtain and maintain all approvals, consents, registrations, permits,
authorizations and other confirmations required to be obtained from any third
party (including consents of the FAA and other Governmental Bodies) that are
necessary, proper or advisable to consummate the transactions contemplated by
this Agreement; provided, however, Purchaser shall not be required to divest or
hold separate or otherwise take or commit to take any action that limits its
freedom of action with respect to any material portion of the Assets of
Purchaser or any of the Purchaser's business. At Purchaser's request, Seller
will commit to and implement any divestiture, hold separate or similar
transaction or action with respect to any asset or business of the Seller, which
commitment and implementation may, at Seller's option, be conditioned upon and
effective as of the Closing Date. Subject to applicable laws relating to the
exchange of information, Purchaser and Seller shall have the right to review in
advance, and to the extent practicable to consult with each other on, all the
information relating to


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<PAGE>   15
Seller and any of its Subsidiaries or Purchaser, as applicable, that appears in
any filing made with, or written materials submitted to, any third party and/or
any Governmental Bodies in connection with the transactions contemplate hereby.

               (b) As promptly as practicable after the execution and delivery
of this Agreement, Purchaser and Seller shall prepare all appropriate
applications for FCC approval, and such other documents as may be required, with
respect to the transfer of control of the FCC Licenses of Seller (collectively,
the "FCC Applications"). Not later than the tenth Business Day following
execution and delivery of this Agreement, Seller and Purchaser will exchange
with each other their respective completed portions of the FCC Applications. Not
later than the fifteenth Business Day following the execution and delivery of
this Agreement, Seller and Purchaser shall file, or cause to be filed, the FCC
Applications. If the Closing Date shall not have occurred for any reason within
any applicable initial consummation period, as provided in the Reorganization
Agreement, and the Reorganization Agreement shall not have been terminated
pursuant to Section 10.1 of the Reorganization Agreement, Purchaser and Seller
shall jointly request one or more extensions of the consummation period of such
grant. No party hereto shall knowingly take, or fail to take, any action if the
intent or reasonably anticipated consequence of such action or failure to act
is, or would be, to cause the FCC not to grant approval of the FCC Applications
or delay either such approval or the consummation of the transfer of the FCC
Licenses of Seller. Seller and Purchaser shall each pay one-half (1/2) of any
FCC fees, if applicable, in connection with the filing or granting of approval
of the FCC Applications. Each of Seller and Purchaser shall bear its own
expenses in connection with the preparation and prosecution of the FCC
Applications. Seller and Purchaser shall each use all reasonable efforts to
prosecute the FCC Applications in good faith and with due diligence before the
FCC and in connection therewith shall take such action or actions as may be
necessary or reasonably required in connection with the FCC Applications,
including furnishing to the FCC any documents, materials or other information
requested by the FCC in order to obtain such FCC approval as expeditiously as
practicable.

               (c) Promptly after the date hereof, Purchaser and Seller (as may
be required pursuant to the HSR Act) will complete all documents required to be
filed with the Federal Trade Commission and the Department of Justice in order
to comply with the HSR Act and, not later than 10 Business Days after the date
hereof, together with the Persons who are required to join in such filings,
shall file the same with the appropriate Governmental Bodies. Purchaser and
Seller shall each pay one-half (1/2) of any fees that may be payable in
connection with the filing pursuant to the HSR Act. Purchaser and Seller shall
promptly furnish all materials thereafter required by any of the Governmental
Bodies having jurisdiction over such filings, and shall take all reasonable
actions and shall file and use all reasonable efforts to have declared effective
or approved all documents and notifications with any such Governmental Bodies,
as may be required


                                       14


<PAGE>   16
under the HSR Act or other federal antitrust laws for the consummation of the
transactions contemplated hereby.

               (d) In addition to the filings required by the HSR Act and the
Communications Act, the Parties shall (i) as promptly as possible and in any
event within 15 days after the date hereof file with any other applicable
Governmental Bodies (including, but not limited to the FAA) the applications and
related documents required to be filed by such Governmental Bodies (and
prosecute diligently any such applications, including providing such information
as such Governmental Bodies may reasonably request) in order to consummate the
transactions, (ii) cooperate with each other as may reasonably be requested in
connection with the foregoing, and (iii) otherwise use their best efforts to
obtain promptly the requested consent and approval of the applications by any
applicable Governmental Bodies. Purchaser and Seller shall each pay one half
(1/2) of all filing or other Governmental Body filing or grant fees in
connection with the applications requesting its consent to the consummation of
the transactions contemplated by this Agreement.

        8.2 Public Announcements. So long as this Agreement is in effect,
Purchaser and Seller will consult with each other before issuing any press
release or making any public statement with respect to the transactions
contemplated by this Agreement and except as may be required by applicable law
or any listing agreement with any national securities exchange, will not issue
any such press release or make any such public statement without the prior
consent of the other party, which consent shall not be unreasonably withheld or
delayed. Notwithstanding the foregoing, any such press release or public
statement as may be required by applicable law or any listing agreement with any
national securities exchange or NASDAQ may be issued without such consent, if
the party making such release or statement has used its reasonable efforts to
consult with the other party.

        8.3 Further Assurances. At and after the Closing Date, the officers and
directors of Purchaser will be authorized to execute and deliver, in the name
and on behalf of Seller, any deeds, bills of sale, assignments or assurances and
to take and do, in the name and on behalf of Purchaser or Seller any other
actions and things to vest, perfect or confirm of record in Purchaser any and
all right, title and interest in, to and under any of the FCC Licenses rights,
properties or Assets of Seller or Purchaser acquired or to be acquired by
Purchaser as a result of, or in connection with, the transactions contemplated
by this Agreement.

        8.4 Notices of Certain Events. Each of Purchaser and Seller shall
promptly notify the other of:

               (a) any notice or other communication from any Person alleging
that the consent of such Person is or may be required in connection with the
transactions contemplated by this Agreement;


                                       15


<PAGE>   17
               (b) any notice or other communication from any Governmental Body
in connection with the transactions contemplated by this Agreement;


               (c) the occurrence, or non-occurrence, of any event the
occurrence, or non-occurrence, of which would be reasonably expected to cause
any representation or warranty made by it and contained herein to be untrue or
inaccurate in any material respect at any time during the period commencing on
the date hereof and ending at the Closing Date;

               (d) any failure of such party to comply with or satisfy any
covenant, condition or agreement to be complied with or satisfied by it
hereunder; provided, however, that the delivery of any notice pursuant to this
Section 8.4 shall not limit or otherwise affect the remedies available hereunder
to the party receiving such notice;

               (e) any actions, suits, claims, investigations or proceedings
commenced or, to its knowledge threatened against such party, or which relate to
the consummation of the transactions contemplated by this Agreement; and

               (f) any event, condition or state of facts which could have a
Seller Material Adverse Effect or a Purchaser Material Adverse Effect.


                                    ARTICLE 9

                              Conditions to Closing

        9.1 Conditions to the Obligations of Each Party. The obligations of
Seller and Purchaser to consummate the Closing are subject to the satisfaction
of the following conditions:

               (a) any applicable waiting period under the HSR Act relating to
the transactions contemplated hereby shall have expired or been terminated;

               (b) no provision of any applicable law or regulation and no
judgment, injunction, order or decree shall prohibit the consummation of the
transactions contemplated hereby;

               (c) all Governmental Consents shall have been obtained and be in
effect, and be subject to no limitations, conditions, restrictions or


                                       16


<PAGE>   18
obligations, except for such consents the failure to obtain would not, and such
limitations, conditions, restrictions or obligation as would not, individually
or in the aggregate, be reasonably expected to have a Seller Material Adverse
Effect or Purchaser Material Adverse Effect;

               (d) no court, arbitrator or Governmental Body shall have issued
any order, and there shall not be any statute, rule or regulation restraining or
prohibiting the effective operation of the business of Purchaser or Seller after
the Closing that would be reasonably expected to have a Purchaser Material
Adverse Effect (after giving effect to the transactions contemplated hereby);

               (e) the FCC Consent shall have become a Final Order and shall not
contain any conditions with respect to Seller or Purchaser, which conditions
would have a Seller Material Adverse Effect or Purchaser Material Adverse
Effect; and

               (f) all conditions set forth in Article 9 of the Reorganization
Agreement have been satisfied or expressly waived in writing.

        9.2 Conditions to the Obligations of Purchaser. The obligations of
Purchaser to consummate the Closing are subject to the satisfaction of the
following further conditions:

               (a) (i) Seller shall have performed in all material respects all
of its obligations hereunder and under the Reorganization Agreement required to
be performed by it at or prior to the Closing, (ii) the representations and
warranties of Seller contained in this Agreement and in any certificate or other
writing delivered by Seller pursuant hereto, disregarding all qualifications and
exceptions contained therein relating to materiality or a Seller Material
Adverse Effect or any similar standard or qualification, shall be true and
correct at and as of the Closing, as if made at and as of such time (other than
representations or warranties that address matters only as of a certain date,
which shall be true and correct as of such date), with only such exceptions as,
individually or in the aggregate, have not had and would not be reasonably
expected to have a Seller Material Adverse Effect, and (iii) Purchaser shall
have received a certificate signed by an executive officer of Seller to the
foregoing effect.

               (b) All conditions to the obligations of Seller and VoiceStream
to close the Transactions contemplated by the Reorganization Agreement shall
have been satisfied or waived, and each of Seller and VoiceStream shall deliver
to Purchaser a certificate signed by an executive officer certifying that the
closing of the Transactions contemplated by the Reorganization Agreement will
occur immediately following the closing of the transactions contemplated herein;
provided, however, that if the Transactions contemplated by the Reorganization
Agreement do not close immediately after the Closing of the transactions
hereunder, the transactions contemplated hereunder shall be void and of no
further force and effect.


                                       17


<PAGE>   19
               (c) All conditions to the obligations of VoiceStream and Cook
Inlet GSM, Inc. to close the transactions contemplated by the VoiceStream
Agreement shall have been satisfied or expressly waived in writing.

        9.3 Conditions to the Obligations of Seller. The obligations of Seller
to consummate the Closing are subject to the satisfaction of the following
further conditions:

               (a) (i) Purchaser shall have performed in all material respects
all of its obligations hereunder required to be performed by it at or prior to
the Closing; (ii) the representations and warranties of Purchaser contained in
this Agreement and in any certificate or other writing delivered by Purchaser
pursuant hereto, disregarding all qualifications and exceptions contained
therein relating to materiality or a Purchaser Material Adverse Effect or any
similar standard or qualification shall be true and correct at and as of the
Closing, as if made at and as of such time (other than representations and
warranties that address matters only as of a certain date, which shall be true
and correct as of such date), with only such exceptions as, individually or in
the aggregate, have not had and would not be reasonably expected to have a
Purchaser Material Adverse Effect; (iii) Seller shall have received a
certificate signed by an executive officer of Purchaser to the foregoing effect;
and (iv) that Cook Inlet GSM, Inc. shall have contributed at least $15 million
to the capital of Purchaser.

               (b) All conditions to the obligations of VoiceStream and Cook
Inlet GSM, Inc. to close the transactions contemplated by the VoiceStream
Agreement shall have been satisfied or expressly waived in writing.


                                   ARTICLE 10

                                   Termination

        10.1 Termination. This Agreement shall be terminated and the
transactions contemplated hereby shall be abandoned upon termination of the
Reorganization Agreement.

        10.2 Effect of Termination. If this Agreement is terminated pursuant to
Section 10.1, this Agreement shall become void and of no effect without
liability of any party (or any stockholder, member, director, officer, employee,
agent, consultant or representative of such party) to the other parties hereto,
except that the agreements contained in this Section 10.2 and in Section 10.3
shall survive the termination hereof and no such termination shall relieve any
party of any liability or damages resulting from any breach by such party of
this Agreement.


                                       18


<PAGE>   20
        10.3 Fees and Expenses. Except as otherwise provided herein, all costs
and expenses incurred in connection with this Agreement shall be paid by the
party incurring such cost or expense whether or not the transactions
contemplated hereby are consummated.


                                   ARTICLE 11

                                  Miscellaneous

        11.1 Notices. All notices, requests and other communications to any
party hereunder shall be in writing (including facsimile transmission) and shall
be given,

                if to Purchaser, to:

                Cook Inlet/VS GSM III PCS, LLC
                2525 "C" Street
                Anchorage, Alaska 99503
                Attention:  Craig A. Floerchinger
                Fax: (907) 263-5181

                with copies to:

                VoiceStream Wireless Corporation
                3650 131 Avenue SE
                Bellevue, Washington 98006
                Attention: Alan R. Bender, Esq.
                Fax: (425) 586-8080

                and:

                Friedman Kaplan & Seiler LLP
                875 Third Avenue
                New York, New York  10022
                Attention:  Barry A. Adelman, Esq.
                Fax: (212) 355-6401

                and:

                Cook Inlet Region Inc.
                2525 "C" Street
                Anchorage, Alaska  99503
                Attention:  General Counsel


                                       19


<PAGE>   21
                Fax: (907) 263-5182

                and:

                Munger, Tolles & Olson LLP
                355 South Grand Ave.
                Los Angeles, California 90071-1560
                Attention: Judith T. Kitano, Esq.
                Fax: (213) 687-3702

                if to Seller, to:

                Omnipoint Corporation
                Three Bethesda Metro Center
                Suite 400
                Bethesda, MD 20814
                Attention: Douglas G. Smith
                Fax: (301) 951-2518

                with copies to:

                Piper & Marbury L.L.P.
                1200 Nineteenth Street, N.W.
                Washington, D.C.  20036
                Attention: Edwin M. Martin, Jr., Esq.
                Fax: (202) 223-2085

or such other address or facsimile number as such party may hereafter specify
for the purpose by notice to the other parties hereto. All such notices,
requests and other communications shall be deemed received on the date of
receipt by the recipient thereof if received prior to 5 p.m. on a Business Day,
in the place of receipt. Otherwise, any such notice, request or communication
shall be deemed not to have been received until the next succeeding Business Day
in the place of receipt.

        11.2 Reliance on Representations. Notwithstanding any investigation
knowledge or review made at any time by or on behalf of any party hereto, the
parties acknowledge and agree that all representations and warranties contained
in this Agreement, or in the Schedules or in any of the documents, certificates
or agreements delivered in connection therewith are being relied upon as a
material inducement to enter into this Agreement and the transactions
contemplated hereby.

        11.3 Survival of Representations and Warranties. The representations and
warranties contained herein and in any certificate or other writing delivered
pursuant


                                       20


<PAGE>   22
hereto shall not survive the Closing Date or, except as provided under Section
10.2 of this Agreement, the termination of this Agreement.

        11.4 Amendments; No Waivers.

               (a) Subject to applicable Delaware Law, any provision of this
Agreement may be amended or waived prior to the Closing Date if, but only if,
such amendment or waiver is in writing and is signed, in the case of an
amendment, by each party to this Agreement or, in the case of a waiver, by each
party against whom the waiver is to be effective.

               (b) No failure or delay by any party in exercising any right,
power or privilege hereunder shall operate as a waiver thereof nor shall any
single or partial exercise thereof preclude any other or further exercise
thereof or the exercise of any other right, power or privilege. The rights and
remedies herein provided shall be cumulative and not exclusive of any rights or
remedies provided by law.

        11.5 Successors and Assigns. The provisions of this Agreement shall be
binding upon and inure to the benefit of the parties hereto and their respective
successors and assigns; provided that no party may assign, delegate or otherwise
transfer any of its rights or obligations under this Agreement without the
consent of each other party hereto.

        11.6 Governing Delaware Law. This Agreement shall be governed by and
construed in accordance with the laws of the State of Delaware, without regard
to the conflicts of law rules of such State.

        11.7 Jurisdiction. Any suit, action or proceeding seeking to enforce any
provision of, or based on any matter arising out of or in connection with, this
Agreement or the transactions contemplated hereby shall be brought in any
federal court located in the State of Delaware or any Delaware state court, and
each of the parties hereby consents to the exclusive jurisdiction of such courts
(and of the appropriate appellate courts therefrom) in any such suit, action or
proceeding and irrevocably waives, to the fullest extent permitted by Delaware
Law, any objection that it may now or hereafter have to the laying of the venue
of any such suit, action or proceeding in any such court or that any such suit,
action or proceeding brought in any such court has been brought in an
inconvenient forum. Process in any such suit, action or proceeding may be served
on any party anywhere in the world, whether within or without the jurisdiction
of any such court. Without limiting the foregoing, each party agrees that
service of process on such party as provided in Section 11.1 shall be deemed
effective service of process on such party.

        11.8 Waiver of Jury Trial. EACH OF THE PARTIES HERETO HEREBY IRREVOCABLY
WAIVES ANY AND ALL RIGHT TO TRIAL BY JURY IN ANY LEGAL PROCEEDING ARISING OUT OF
OR RELATED TO THIS AGREEMENT OR THE TRANSACTIONS CONTEMPLATED HEREBY.


                                       21


<PAGE>   23
        11.9 Counterparts; Effectiveness. This Agreement may be signed in any
number of counterparts, each of which shall be an original, with the same effect
as if the signatures thereto and hereto were upon the same instrument. This
Agreement shall become effective when each party hereto shall have received
counterparts hereof signed by all of the other parties hereto. No provision of
this Agreement is intended to confer any rights, benefits, remedies, obligations
or liabilities hereunder upon any Person other than the parties hereto and their
respective successors and assigns.

        11.10 Entire Agreement; No Third Party Beneficiaries. This Agreement,
constitutes the entire agreement between the parties with respect to the subject
matter of this Agreement and supersedes all prior agreements and understandings,
both oral and written, between the parties with respect to the subject matter of
this Agreement. This Agreement is not intended to confer upon any Person other
than the parties hereto any rights or remedies.

        11.11 Captions. The captions herein are included for convenience of
reference only and shall be ignored in the construction or interpretation
hereof.

        11.12 Severability. If any term, provision, covenant or restriction of
this Agreement is held by a court of competent jurisdiction or other authority
to be invalid, void or unenforceable, the remainder of the terms, provisions,
covenants and restrictions of this Agreement shall remain in full force and
effect and shall in no way be affected, impaired or invalidated so long as the
economic or legal substance of the transactions contemplated hereby is not
affected in any manner materially adverse to any party. Upon such a
determination, the parties shall negotiate in good faith to modify this
Agreement so as to effect the original intent of the parties as closely as
possible in an acceptable manner so that the transactions contemplated hereby be
consummated as originally contemplated to the fullest extent possible.

        11.13 Specific Performance. The parties hereto agree that irreparable
damage would occur if any provision of this Agreement were not performed in
accordance with the terms hereof and that the parties shall be entitled to an
injunction or injunctions to prevent breaches of this Agreement or to enforce
specifically the performance of the terms and provisions hereof in any federal
court located in the State of Delaware or any Delaware state court, in addition
to any other remedy to which they are entitled at Delaware Law or in equity.


                                       22


<PAGE>   24
        IN WITNESS WHEREOF, the parties hereto have caused this Agreement to be
duly executed by their respective authorized officers as of the day and year
first above written.

                                      OMNIPOINT CORPORATION


                                      By:
                                         -------------------------------
                                      Name:
                                      Title:


                                      COOK INLET/VS GSM III PCS, LLC

                                      By: Cook Inlet GSM, Inc., its Manager


                                      By:
                                         -------------------------------
                                      Name:
                                      Title:


                                       23


<PAGE>   25
                                TABLE OF CONTENTS


<TABLE>
<CAPTION>
                                                                                    PAGE
                                                                                    ----
<S>                                                                                 <C>
ARTICLE 1 -- Defined Terms............................................................1
        1.1     (a)    Defined Terms..................................................1


ARTICLE 2 -- Purchase.................................................................8
        2.1     Purchase and Sale.....................................................8
        2.2     Purchase Price........................................................8
        2.3     Closing...............................................................8
        2.4     Bill of Sale..........................................................9

ARTICLE 3 -- Assumption of Certain Liabilities........................................9
        3.1     Assumed Liabilities...................................................9
        3.2     Liabilities Not Assumed...............................................9
        3.3     Assumption Agreement..................................................9

ARTICLE 4 -- Representations and Warranties of Seller................................10

ARTICLE 5 -- Representations and Warranties of Purchaser.............................10
        5.1     Existence and Power..................................................10
        5.2     Corporate Authorization..............................................11
        5.3     Governmental Authorization...........................................11
        5.4     Non-contravention....................................................11
        5.5     Capitalization.......................................................12
        5.6     Finders' Fees........................................................12
        5.7     Formation and Liabilities............................................12

ARTICLE 6 -- Covenants of Seller.....................................................13

ARTICLE 7 -- Covenants of Purchaser..................................................13

ARTICLE 8 -- Covenants of Seller and Purchaser.......................................13
        8.1     Best Efforts.........................................................13
        8.2     Public Announcements.................................................15
        8.3     Further Assurances...................................................15
        8.4     Notices of Certain Events............................................16
</TABLE>


                                        i


<PAGE>   26
<TABLE>
<CAPTION>
                                                                                    PAGE
                                                                                    ----
<S>                                                                                 <C>
ARTICLE 9 -- Conditions to Closing...................................................16
        9.1     Conditions to the Obligations of Each Party..........................16
        9.2     Conditions to the Obligations of Purchaser...........................17
        9.3     Conditions to the Obligations of Seller..............................18

ARTICLE 10 -- Termination............................................................18
        10.1    Termination..........................................................19
        10.2    Effect of Termination................................................19
        10.3    Fees and Expenses....................................................19

ARTICLE 11 -- Miscellaneous..........................................................19
        11.1    Notices..............................................................19
        11.2    Reliance on Representations..........................................21
        11.3    Survival of Representations and Warranties...........................21
        11.4    Amendments; No Waivers...............................................21
        11.5     Successors and Assigns..............................................21
        11.6    Governing Delaware Law...............................................21
        11.7    Jurisdiction.........................................................21
        11.8    Waiver of Jury Trial.................................................22
        11.9    Counterparts; Effectiveness..........................................22
        11.10   Entire Agreement; No Third Party Beneficiaries.......................22
        11.11   Captions.............................................................22
        11.12   Severability.........................................................22
        11.13   Specific Performance.................................................23
</TABLE>


                                       ii


<PAGE>   27
                                    SCHEDULES

        Schedule Number      Name

        Schedule I           FCC Licenses

        Schedule 3.1(a)      Schedule I Assumed Liabilities


                                       iii


<PAGE>   28
                                 Schedule 3.1(a)


                                      None


                                       iv