<PAGE>   1
                                                                     EXHIBIT 9.1


                                    AGREEMENT

     AGREEMENT, dated as of June 23, 1999, by and among OMNIPOINT CORPORATION, a
Delaware corporation ("Omnipoint"), VOICESTREAM WIRELESS CORPORATION, a
Washington corporation ("VoiceStream"), the individuals and entities set forth
on Schedule I hereto (each, an "Omnipoint Stockholder" and, collectively, the
"Omnipoint Stockholders") and the individuals and entities set forth on Schedule
II hereto (each, a "VoiceStream Stockholder" and, collectively, the "VoiceStream
Stockholders").

     WHEREAS, concurrently herewith, each of Omnipoint and 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 ("Newco"), will
be merged with and into each of Omnipoint and VoiceStream (such mergers,
together with the related transactions contemplated in the Reorganization
Agreement, being referred to herein collectively as the "Merger");

     WHEREAS, each Omnipoint Stockholder is the beneficial owner of the number
of shares of Omnipoint Common Stock set forth opposite such Omnipoint
Stockholder's name in Schedule I hereto (the "Omnipoint Shares");

     WHEREAS, each VoiceStream Stockholder is the beneficial owner of the number
of shares of VoiceStream Common Stock set forth opposite such VoiceStream
Stockholder's name in Schedule II hereto (the "VoiceStream Scheduled Shares");

     WHEREAS, approval of the Reorganization Agreement by each of Omnipoint's
and VoiceStream's stockholders is a condition to the consummation of the Merger;
and

     WHEREAS, as a condition to its entering into the Reorganization Agreement,
(i) VoiceStream has required that each Omnipoint Stockholder agree, and each
Omnipoint Stockholder has agreed, to enter into this Agreement, and (ii)
Omnipoint has required that each VoiceStream Stockholder agree, and each
VoiceStream Stockholder has agreed, to enter into this Agreement;

     NOW THEREFORE, in consideration of the foregoing and the mutual covenants
and agreements set forth herein, the parties hereto agree as follows:

     Section 1. Definitions. Capitalized terms used herein and not otherwise
defined have the meaning ascribed to such term in the Reorganization Agreement.

<PAGE>   2



     Section 2. Agreement to Vote by Omnipoint Stockholders.

     (a) Each Omnipoint Stockholder hereby agrees to attend the Omnipoint
Stockholders' Meeting, in person or by proxy, and to vote (or cause to be voted)
all Omnipoint Shares, and any other voting securities of Omnipoint, beneficially
owned by such Omnipoint Stockholder (whether issued heretofore or hereafter)
that such Omnipoint Stockholder owns or has the right to vote, (i) in favor of
adoption and approval of the Reorganization Agreement and the Merger and any
other matters necessary to consummate the transactions contemplated in the
Reorganization Agreement and (ii) against any Acquisition Proposal; such
agreement to vote shall apply also to any adjournment or adjournments of the
Omnipoint Stockholders' Meeting.

     (b) From and after the date hereof through the earlier of the Effective
Time or the termination of the Reorganization Agreement, each Omnipoint
Stockholder (other than with respect to any distribution by Madison Dearborn
Capital Partners, L.P. of its Omnipoint Shares to its partners) hereby agrees
not to sell, transfer, pledge, encumber or otherwise dispose of (collectively,
"Transfer") in the aggregate and whether in a single transaction or a series of
unrelated transactions more than thirty (30%) percent of the Omnipoint Shares
beneficially owned by such Omnipoint Stockholder on the date hereof, unless, as
a condition to any such Transfer, each transferee (or, in the case of a pledge
or similar transfer, each pledgee or similar conditional transferee) of any
shares in excess of thirty (30%) percent of the Omnipoint Shares beneficially
owned by such Omnipoint Stockholder shall, prior to such Transfer (or, in the
case of a pledge or similar Transfer, prior to taking title to or exercising any
rights with respect to the applicable Omnipoint Shares), agree in writing to be
bound by all of the provisions of this Agreement applicable to the Omnipoint
Stockholders (and such transferee shall thereby become an Omnipoint Stockholder
for all purposes of this Agreement), except that such Transferee shall not be
entitled to Transfer any such shares unless all transferees of all shares so
transferred agree to be bound by the terms of Section 2(a) hereof and such
Transferee (and such Transferee's transferees) shall not be entitled to the
benefits of the exception applicable to the Omnipoint Stockholders with respect
to 30% of the Omnipoint Shares beneficially owned by them. Any Transfer of such
shares and securities without compliance with such provisions of this Agreement
shall be null and void and such transferee shall have no rights as a stockholder
of Omnipoint.

     (c) To the extent inconsistent with the foregoing provisions of this
Section 2, each Omnipoint Stockholder hereby revokes any and all previous
proxies with respect to such Omnipoint Stockholder's Omnipoint Shares or any
other voting securities of Omnipoint.

     Section 3. Agreement to Vote by VoiceStream Stockholders.

     (a) Each VoiceStream Stockholder hereby agrees to attend the VoiceStream
Stockholders' Meeting, in person or by proxy, and to vote (or cause to be voted)
all VoiceStream Scheduled Shares owned by such VoiceStream Stockholder at the
time of the VoiceStream



                                       2
<PAGE>   3

Stockholders' Meeting in favor of adoption and approval of the Reorganization
Agreement, the Merger and the Hutchison Transaction and any other matters
necessary to consummate the transactions contemplated in the Reorganization
Agreement; such agreement to vote shall apply also to any adjournment or
adjournments of the VoiceStream Stockholders' Meeting.

     (b) From and after the date hereof through the earlier of the Effective
Time or the termination of the Reorganization Agreement, each VoiceStream
Stockholder (other than with respect to any distribution by Hellman & Friedman
Capital Partners II, L.P., H&F Orchard Partners, L.P., H&F International
Partners, L.P., GS Capital Partners, L.P., Bridge Street Fund 1992, L.P., Stone
Street Fund 1992, L.P. or Providence Media Partners L.P. of their VoiceStream
shares to their partners) hereby agrees not to Transfer in the aggregate and
whether in a single transaction or a series of unrelated transactions more than
(30%) percent of the VoiceStream Scheduled Shares, unless, as a condition to any
such Transfer, each transferee (or, in the case of a pledge or similar transfer,
each pledgee or similar conditional transferee) of any shares in excess of
thirty (30%) percent of the VoiceStream Scheduled Shares, prior to such Transfer
(or, in the case of a pledge or similar transfer, prior to taking title to or
exercising any rights with respect to the applicable VoiceStream Scheduled
Shares), agree in writing to be bound by all of the provisions of this Agreement
applicable to the VoiceStream Stockholders (and such transferee shall thereby
become a VoiceStream Stockholder for all purposes of this Agreement), except
that such Transferee shall not be entitled to Transfer any such shares unless
all transferees of all shares so transferred agree to be bound by the terms of
Section 3(a) hereof and such Transferee (and such Transferee's transferees)
shall not be entitled to the benefits of the exception applicable to the
VoiceStream Stockholders with respect to 30% of the VoiceStream Scheduled
Shares. Any Transfer of such shares and securities without compliance with such
provisions of this Agreement shall be null and void and such transferee shall
have no rights as a stockholder of VoiceStream.

     (c) To the extent inconsistent with the foregoing provisions of this
Section 3, each VoiceStream Stockholder hereby revokes any and all previous
proxies with respect to such VoiceStream Stockholder's VoiceStream Scheduled
Shares.

     Section 4. Amendment of Existing VoiceStream Voting Agreement.

     The VoiceStream Stockholders are parties to a Voting Agreement, dated May
3, 1999 ("VoiceStream Voting Agreement"), pursuant to which they have agreed to
vote their VoiceStream Scheduled Shares owned by each of them at the time of
such vote in favor of directors designated by such VoiceStream Stockholders.
Effective on the Effective Time the VoiceStream Stockholders shall terminate the
VoiceStream Voting Agreement and enter into a new Voting Agreement ("Newco
Voting Agreement") with the Omnipoint Stockholders on terms mutually
satisfactory to the VoiceStream Stockholders and the Omnipoint Stockholders,
pursuant to which the voting arrangements which existed under the VoiceStream
Voting Agreement will apply to Newco and the provisions of Section 6.1 of the
Securities Purchase Agreement, of even date herewith, between VoiceStream and
Omnipoint, will also be effectuated.




                                       3
<PAGE>   4

     Section 5. Representations and Warranties of VoiceStream and Omnipoint.

     (a) VoiceStream represents and warrants to Omnipoint and each Omnipoint
Stockholder as follows: (i) each of this Agreement and the Reorganization
Agreement has been approved by the Board of Directors of VoiceStream and (ii)
each of this Agreement and the Reorganization Agreement has been duly executed
and delivered by VoiceStream and constitutes its valid and binding agreement,
enforceable against it in accordance with its terms, except as may be limited by
applicable bankruptcy, insolvency, reorganization, moratorium and other similar
laws of general application which may affect the enforcement of creditors'
rights generally and by general equitable principles.

     (b) Omnipoint represents and warrants to VoiceStream and each VoiceStream
Stockholder as follows: (i) each of this Agreement and the Reorganization
Agreement has been approved by the Board of Directors of Omnipoint and (ii) each
of this Agreement and the Reorganization Agreement has been duly executed and
delivered by Omnipoint and constitutes its valid and binding agreement,
enforceable against it in accordance with its terms, except as may be limited by
applicable bankruptcy, insolvency, reorganization, moratorium and other similar
laws of general application which may affect the enforcement of creditors'
rights generally and by general equitable principles.

     Section 6. Representations and Warranties of the Omnipoint Stockholders and
VoiceStream Stockholders.

     (a) Each Omnipoint Stockholder, severally, as to such Omnipoint
Stockholder, represents and warrants to VoiceStream as follows: (i) this
Agreement has been duly executed and delivered by such Omnipoint Stockholder and
constitutes its valid and binding agreement, enforceable against it in
accordance with its terms, except as may be limited by applicable bankruptcy,
insolvency, reorganization, moratorium and other similar laws of general
application which may affect the enforcement of creditors' rights generally and
by general equitable principles; and (ii) the Omnipoint Shares listed next to
the name of such Omnipoint Stockholder on Schedule I hereto are the only voting
securities of Omnipoint owned (beneficially or of record) by it.

     (b) Each VoiceStream Stockholder, severally, as to such VoiceStream
Stockholder, represents and warrants to Omnipoint that this Agreement has been
duly executed and delivered by such VoiceStream Stockholder and constitutes its
valid and binding agreement, enforceable against it in accordance with its
terms, except as may be limited by applicable bankruptcy, insolvency,
reorganization, moratorium and other similar laws of general application which
may affect the enforcement of creditors' rights generally and by general
equitable principles.

     Section 7. Effectiveness and Termination. It is a condition precedent to
the effectiveness of this Agreement that the Reorganization Agreement shall have
been executed and delivered and be in full force and effect. In the event the
Reorganization Agreement is terminated in accordance with its terms, this
Agreement shall automatically terminate and be of no further force



                                       4
<PAGE>   5

or effect. Upon such termination, except for any rights any party may have in
respect of any breach by any other party of its or his obligations hereunder,
none of the parties hereto shall have any further obligation or liability
hereunder.

     Section 8. Miscellaneous.

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

if to VoiceStream, to it at:

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

with a copy to:

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

if to any VoiceStream Stockholder, to it at the address set forth on Schedule II
hereto;

if to Omnipoint, to it at:

                           Omnipoint Corporation
                           3 Bethesda Metro Center
                           Suite 400
                           Bethesda, Maryland 20814
                           Attention: Douglas G. Smith
                           Fax: 301-951-3591

with a copy to:

                           Piper & Marbury L.L.P.
                           1200 Nineteenth Street, N.W.
                           Washington, D.C.  20036
                           Attention: Edwin M. Martin, Jr., Esq.
                           Fax: (202) 233-2085


                                       5
<PAGE>   6

     if to any Omnipoint Stockholder, to it at the address set forth on Schedule
I hereto;

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.

     (b) Amendments; No Waivers. (i) Subject to applicable law, any provision of
this Agreement may be amended or waived, 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.

          (ii) 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.

     (c) Successors and Assigns. This Agreement shall be binding upon and shall
inure to the benefit of and be enforceable by the parties and their respective
successors and assigns, including, without limitation, in the case of any
corporate party hereto any corporate successor by merger or otherwise, and in
the case of any individual party hereto any trustee, executor, heir, legatee or
personal representative succeeding to the ownership of such party's shares of
Omnipoint Common Stock or other securities subject to this Agreement.
Notwithstanding any Transfer of shares of Omnipoint Common Stock the transferor
shall remain liable for the performance of all obligations under this Agreement
of transferor.

     (d) Governing 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.

     (e) 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 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



                                       6
<PAGE>   7

party agrees that service of process on such party as provided in Section 6(e)
shall be deemed effective service of process on such party.

     (f) 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.

     (g) 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.

     (h) Entire Agreement. This Agreement, together with the Reorganization
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 such
subject matter.

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

     (j) 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.

     (k) 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 law or in equity.

     (l) Remedies Cumulative. All rights, powers and remedies provided under
this Agreement or otherwise available in respect hereof at law or in equity
shall be cumulative and not



                                       7
<PAGE>   8

alternative, and the exercise or beginning of the exercise of any thereof by any
party shall not preclude the simultaneous or later exercise of any other such
right, power or remedy by such party.

     (m) Limitation on Liability. No party hereto shall have any liability
hereunder for any actions or omissions of any other party hereto.

     (n) Expenses. Each party hereto shall bear its own expenses incurred in
connection with this Agreement.

     (o) Further Assurances. Each party hereto agrees that such party shall
execute and deliver such additional instruments and other documents and shall
take such further actions as may be necessary or appropriate to effectuate,
carry out and comply with all of their obligations under this Agreement. Without
limiting the generality of the foregoing, none of the parties hereto shall enter
into any agreement or arrangement (or alter, amend or terminate any existing
agreement or arrangement) if such action would impair the ability of any party
to effectuate, carry out or comply with all the terms of this Agreement.



                                       8
<PAGE>   9

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

                 VOICESTREAM WIRELESS CORPORATION


                 By:     /John Stanton/
                         -----------------------------------
                          Name:
                          Title:


                 OMNIPOINT CORPORATION



                 By:     /Douglas G. Smith/
                         -----------------------------------
                          Name:
                          Title:



                 VOICESTREAM STOCKHOLDERS:

                 Hellman & Friedman Capital Partners II, L.P., a
                 California limited partnership


                 By:      Hellman & Friedman Investors, L.P., its
                          general partner

                          By:      Hellman & Friedman Investors, Inc., its
                                   general partner



                          By:     /Mitchell Cohen/
                              -----------------------------------
                                   Name:
                                   Title:



<PAGE>   10

            H&F Orchard Partners, L.P., a California limited
            partnership

            By:      H&F Orchard Investors, L.P., its general
                     partner

                     By:      H&F Orchard Investors, Inc., its general
                              partner


                     By:     /Mitchell Cohen/
                             ----------------------------------------
                              Name:
                              Title:


            H&F International Partners, L.P., a California limited
            partnership

            By:      H&F International Investors, L.P., its general
                     partner

                     By:      H&F International Investors, Inc., its
                              general partner


                     By:     /Mitchell Cohen/
                             ----------------------------------------
                              Name:
                              Title:



                 /John W. Stanton/
           -------------------------------------
            John W. Stanton



                 /Theresa E. Gillespie/
           -------------------------------------
           Theresa E. Gillespie
<PAGE>   11



                 PN Cellular, Inc.



                 By:     /John W. Stanton/
                         ----------------------------------------
                          Name:
                          Title:

                 Stanton Family Trust



                 By:     /Don Guthrie/
                         ----------------------------------------
                          Name:       , Trustee


                 Stanton Communications Corporation



                 By:     /John W. Stanton/
                         ----------------------------------------
                          Name:
                          Title:


                 GS Capital Partners, L.P.

                 By:      GS Advisors L.P., General Partner

                          By:      GS Advisors, Inc., General Partner


                          By:     /Eve M. Gerriets/
                                  ----------------------------------------
                                   Name:
                                   Title:


                 The Goldman Sachs Group, Inc.


                 By:     /Terrence M. O'Toole/
                         ----------------------------------------
                          Name:
                          Title:

<PAGE>   12



                       Bridge Street Fund 1992, L.P.


                       By:      Stone Street Performance Corp., Managing
                                General Partner


                                By:     /Eve M. Gerriets/
                                      ----------------------------------------
                                      Name:
                                      Title:


                       Stone Street Fund 1992, L.P.


                       By:      Stone Street Performance Corp., General
                                Partner


                                 By:     /Eve M. Gerriets/
                                        ---------------------------------------
                                        Name:
                                        Title:


                       Providence Media Partners L.P.


                       By:      Providence Media G.P. Limited Partnership,
                                General Partner

                                 By:      Providence Ventures L.P., General
                                          Partner



                                 By:     /Jonathan Madison/
                                         --------------------------------------
                                         Name:
                                         Title:

<PAGE>   13



                             Hutchison Telecommunications Holdings (USA)
                             Limited



                             By:     /Susan Chow/
                                      ----------------------------------------
                                      Name:
                                      Title:


                             Hutchison Telecommunications PCS (USA) Limited



                             By:     /Frank Sixt/
                                     ----------------------------------------
                                     Name:
                                     Title:

<PAGE>   14



                         ALLEN & COMPANY INCORPORATED


                         By:     /Richard Fields/
                            ----------------------------------------
                            Name:
                            Title:

                         AVANCE CAPITAL

                         By:     /Douglas G. Smith/
                            ----------------------------------------
                            Name:  Douglas G. Smith
                            Title:  Sole Proprietor

                         MADISON DEARBORN CAPITAL
                         PARTNERS, L.P.

                         By: Madison Dearborn Partners, L.P.,
                            its General Partner


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

                         DOUGLAS G. SMITH GRAT


                         By:     /Gabriela Smith/
                            ----------------------------------------
                            Name:  Gabriela Smith
                            Title: Trustee


                         By:     /Richard Fields/
                            ----------------------------------------
                            Richard Fields, in his individual capacity


                         By:     /Evelyn R. Goldfine/
                            ----------------------------------------------
                            Evelyn R. Goldfine, in her individual capacity

<PAGE>   15



                            By:     /George F. Schmitt/
                              ----------------------------------------
                               George F. Schmitt, in his individual capacity


                            By:     /James J. Ross/
                              ----------------------------------------
                               James J. Ross, in his individual capacity

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


                            By:     /James J. Ross/
                              ----------------------------------------
                               Name:  James J. Ross
                               Title: Trustee

<PAGE>   16



                             Omnipoint Stockholders:

                                [TO BE PROVIDED]




<PAGE>   17


                                                                     SCHEDULE I

                             OMNIPOINT STOCKHOLDERS
<TABLE>
<CAPTION>


      NAME AND ADDRESS OF STOCKHOLDER               NUMBER OF OMNIPOINT SHARES
______________________________________              ___________________________
<S>                                                <C>

______________________________________              ___________________________


______________________________________              ___________________________


______________________________________              ___________________________


______________________________________              ___________________________
</TABLE>


<PAGE>   18



                                                                    SCHEDULE II

                            VOICESTREAM STOCKHOLDERS
<TABLE>
<CAPTION>

                                                          NUMBER OF VOICESTREAM
     NAME AND ADDRESS OF STOCKHOLDER                         SCHEDULED SHARES
------------------------------------------                ----------------------
<S>                                                       <C>
Hellman & Friedman Capital Partners II, L.P.                      6,592,285
c/o Hellman & Friedman LLC
One Maritime Plaza, Suite 1200
San Francisco, California 94111
Attention: Mitchell R. Cohen
Fax:  415-788-0176
--------------------------------------------------------------------------------
H&F Orchard Partners, L.P.                                          589,693
c/o Hellman & Friedman
One Maritime Plaza, Suite 1200
San Francisco, California 94111
Attention: Mitchell R. Cohen
Fax:  415-788-0176
H&F International Partners, L.P.                                    117,019
c/o Hellman & Friedman
One Maritime Plaza, Suite 1200
San Francisco, California 94111
Attention: Mitchell R. Cohen
Fax:  415-788-0176
--------------------------------------------------------------------------------
John W. Stanton and Theresa E. Gillespie                          3,192,774
c/o VoiceStream Wireless Corporation
3650 131st Avenue S.E., Suite 400
Bellevue, WA 98006
Attention:  John W. Stanton
Fax: 425-586-8010
--------------------------------------------------------------------------------
PN Cellular, Inc.                                                 1,686,069
c/o VoiceStream Wireless Corporation
3650 131st Avenue S.E., Suite 400
Bellevue, WA 98006
Attention:  John W. Stanton
Fax: 425-586-8010
</TABLE>

<PAGE>   19
<TABLE>

<S>                                                            <C>
Stanton Family Trust                                                    164,437
c/o VoiceStream Wireless Corporation
3650 131st Avenue S.E., Suite 400
Bellevue, WA 98006
Attention:  John W. Stanton
Fax: 425-586-8010
--------------------------------------------------------------------------------
Stanton Communications Corporation                                    1,274,520
c/o VoiceStream Wireless Corporation
3650 131st Avenue S.E., Suite 400
Bellevue, WA 98006
Attention:  John W. Stanton
Fax: 425-586-8010
--------------------------------------------------------------------------------
GS Capital Partners, L.P.                                             8,986,738
c/o Goldman, Sachs & Co.
85 Broad Street
New York, NY 10004
Attention:  Terence O'Toole
Fax: 212-902-3000
--------------------------------------------------------------------------------
The Goldman Sachs Group, Inc.                                            68,821
c/o Goldman, Sachs & Co.
85 Broad Street
New York, NY 10004
Attention:  Terence O'Toole
Fax: 212-902-3000
--------------------------------------------------------------------------------
Bridge Street Fund 1992, L.P.                                           273,069
c/o Goldman, Sachs & Co.
85 Broad Street
New York, NY 10004
Attention:  Terence O'Toole
Fax: 212-902-3000
--------------------------------------------------------------------------------
Stone Street Fund 1992, L.P.                                            470,401
c/o Goldman, Sachs & Co.
85 Broad Street
New York, NY 10004
Attention:  Terence O'Toole
Fax: 212-902-3000

</TABLE>

<PAGE>   20

<TABLE>

<S>                                                                <C>
Providence Media Partners L.P.                                        2,640,049
c/o Providence Ventures, Inc.
900 Fleet Center
50 Kennedy Plaza
Providence, Rhode Island 02903
Attention: Jonathan Nelson
Fax: 401-751-1790
--------------------------------------------------------------------------------
Hutchison Telecommunications PCS (USA) Limited                       19,010,364

c/o Offshore Incorporations Limited
P.O. Box 957
Offshore Incorporations Centre
Road Town, Tortola
British Virgin Islands
Telephone No.: 809-494-2233
Facsimile No.: 809-494-4885

and:

c/o Hutchison Telecommunications Limited
22nd Floor, Hutchison House
10 Harcourt Road
Hong Kong
Attention: Ms. Edith Shih
Fax: 852-2128-1778

</TABLE>


<PAGE>   21

<TABLE>


<S>                                                                  <C>
Hutchison Telecommunications Holdings (USA) Limited                     3,888,888

c/o Offshore Incorporations Limited
P.O. Box 957
Offshore Incorporations Centre
Road Town, Tortola
British Virgin Islands
Telephone No.: 809-494-2233
Facsimile No.: 809-494-4885

and:

c/o Hutchison Telecommunications Limited
22nd Floor, Hutchison House
10 Harcourt Road
Hong Kong
Attention: Ms. Edith Shih
Fax: 852-2128-1778

</TABLE>