<PAGE>

                                                                     Exhibit 3.1

                                AMENDED BYLAWS OF
                                 i3 MOBILE, INC.

                                    ARTICLE I

                                     OFFICES

     Section 1.   Registered Office. The registered office of the above-named
corporation shall be located at 1013 Centre Road, Wilmington, Delaware 19805.

     Section 2.   Other Offices. The corporation may also have offices at such
other places both within and without the State of Delaware as the board of
directors may from time to time determine in the business of the corporation may
require.

                                   ARTICLE II

                            MEETINGS OF STOCKHOLDERS

     Section 1.   Time and Place. All meetings of the stockholders for any
purpose shall be held at such time and place, either within or without the State
of Delaware, as shall be designated from time to time by the board of directors
and stated in the notice of the meeting or in a duly executed waiver of notice
thereof.

     Section 2.   Annual Meeting. Annual meetings of stockholders, commencing
with the year 1998, shall be held on the first Tuesday in July if not a legal
holiday, and, if a legal holiday, then on the next business day following, at
11:00 A.M., or at such other date and time as shall be designated from time to
time by the board of directors. For the purposes of these bylaws a "business
day" shall mean any day other than a Saturday, a Sunday or a day on which
banking institutions in The City of New York, New York are authorized or
obligated by law or executive order to be closed. At the annual meeting, holders
of the corporation's voting stock, shall elect, by a plurality vote, a board of
directors and transact such other business as may properly be brought before the
meeting.

     Section 3.   Notice of Annual Meeting. Written notice of the annual
meeting, stating the place, date and time of the meeting, shall be given to each
stockholder entitled to vote at such meeting not less than ten (10) nor more
than sixty (60) days before the date of the meeting.

     Section 4.   List of Stockholders. The officer who has charge of the stock
ledger of the corporation shall prepare and make, at least ten (10) days before
every meeting of stockholders, a complete list of the stockholders entitled to
vote at the meeting, arranged in alphabetical order, and showing the address of
each stockholder and the number of shares registered in the name of each
stockholder. Such list shall be open to the examination of any stockholder, for
any purpose germane to the meeting, during ordinary business hours, for a period
of at least ten (10) days prior to the meeting either at a place within the city
where the meeting is to be held, which place shall be specified in the notice of
the meeting or, if not so specified, at the place where the

<PAGE>

meeting is to be held. The list shall also be produced and kept at the time and
place of the meeting during the whole time thereof, and may be inspected by any
stockholder who is present.

     Section 5.   Special Meetings. Special meetings of the stockholders for any
purpose or purposes, unless otherwise prescribed by statute or by the
certificate of incorporation, may be called by the chief executive officer and
shall be called by the chief executive officer or the secretary at the request
in writing of a majority of the board of directors or at the request in writing
of stockholders owning ten percent (10%) in amount of the entire capital stock
of the corporation issued and outstanding and entitled to vote. Such request
shall state the purpose or purposes of the proposed meeting.

     Section 6.   Notice of Special Meetings. Written notice of a special
meeting, stating the place, date and time of the meeting and the purpose or
purposes for which the meeting is called, shall be given not less than ten (10)
nor more than sixty (60) days before the date of the meeting, to each
stockholder entitled to vote at such meeting.

     Section 7.   Limit on Business at Special Meetings. Business transacted at
any special meeting of stockholders shall be limited to the purposes stated in
the notice.

     Section 8.   Quorums. The holders of a majority of the stock issued and
outstanding and entitled to vote thereat, present in person or represented by
proxy, shall constitute a quorum at all meetings of stockholders for the
transaction of business, except as otherwise provided by statute or by the
certificate of incorporation. If, however, such quorum shall not be present or
represented at any meeting of the stockholders, the stockholders entitled to
vote thereat, present in person or represented by proxy, shall have power to
adjourn the meeting from time to time, without notice other than announcement at
the meeting of the time and place of such adjourned meeting, until a quorum
shall be present by proxy or represented by proxy. At any adjourned meeting at
which a quorum shall be present or represented by proxy, any business may be
transacted which might have been transacted at the meeting as originally called.
If the adjournment is for more than thirty (30) days, or if after the
adjournment a new record date is fixed for the adjourned meeting, a notice of
the adjourned meeting shall be given to each stockholder of record entitled to
vote at the meeting.

     Section 9.   Voting at Meetings. When a quorum is present at any meeting,
the vote of the holders of a majority of the stock having voting power, present
in person or represented by proxy, shall decide any question brought before such
meeting, unless the question is one upon which by express statutory provision or
provision of the certificate of incorporation a different vote is required, in
which case such express provision shall govern and control the decision of such
question.

     Section 10.  Voting Power. Unless otherwise provided in the certificate of
incorporation, each stockholder shall at every meeting of the stockholders be
entitled to one (1) vote in person or by proxy for each share of the capital
stock having voting power held by such stockholder, but no proxy shall be voted
on after three (3) years from its date, unless the proxy provides for a longer
period.

                                       -2-

<PAGE>

     Section 11.  Written Consent Without Meeting. Unless otherwise provided in
the certificate of incorporation, any action required to be taken at any annual
or special meeting of stockholders of the corporation, or any action which may
be taken at any annual or special meeting of such stockholders, may be taken
without a meeting, without prior notice and without a vote, if a consent in
writing, setting forth the action so taken, shall be signed by the holders of
outstanding stock having not less than the minimum number of votes that would be
necessary to authorize or take such action at a meeting at which all shares
entitled to vote thereon were present and voted. Prompt notice of the taking of
corporate action without a meeting by less than unanimous written consent shall
be given to those stockholders who have not consented in writing.

                                  ARTICLE III

                                    DIRECTORS

     Section 1.   General Powers. The business of the corporation shall be
managed by, or under the direction of, its board of directors which may exercise
all such powers of the corporation and do all such lawful acts and things as are
not by statute, the certificate of incorporation or these bylaws directed or
required to be exercised or done by the stockholders.

     Section 2.   Election and Tenure. The number of directors which shall
constitute the whole board shall be a maximum of six (6). Each director shall
hold office until his successor or successors are elected and shall qualify or
until his earlier resignation or removal. Directors need not be stockholders.

     Section 3.   Place of Meetings. The board of directors of the corporation
may hold meetings, both regular and special, either within or without the State
of Delaware.

     Section 4.   Annual Meetings. The first meeting of each newly elected board
of directors shall be held immediately after the annual meeting and no notice of
such meeting shall be necessary to the newly elected directors in order to
legally constitute the meeting, provided a quorum shall be present.

     Section 5.   Regular Meetings. Regular meetings of the board of directors
shall be held at least bi-monthly at such time and at such place as shall from
time to time be determined by the board.

     Section 6.   Special Meetings. Special meetings of the board of directors
may be called by the chief executive officer on two (2) days' notice to each
director, either personally, by mail, by telegram, by telex or by facsimile
transmission; special meetings shall be called by the chief executive officer in
like manner and on like notice upon the written request of a majority of the
directors then in office on one occasion each month. Any notice may be given by
the secretary and need not state the purpose or purposes of the meeting unless
otherwise required by these bylaws.

     Section 7.   Quorum and Adjournments. At all meetings of the board, a
majority of the directors shall constitute a quorum for the transaction of
business, and the act of a majority of the directors present at any meeting at
which there is a quorum shall be the act of the board of

                                       -3-

<PAGE>

directors, except as may be otherwise specifically provided by statute or by the
certificate of incorporation. If a quorum shall not be present at any meeting of
the board of directors, the directors present thereat may adjourn the meeting
from time to time without notice other than announcement at the meeting until a
quorum shall be present.

     Section 8.   Action by Consent. Any action required or permitted to be
taken at any meeting of the board of directors or of any committee thereof may
be taken without a meeting if all members of the board of directors or
committee, as the case may be, consent thereto in writing and the writing is
filed with the minutes of the proceedings of the board or committee.

     Section 9.   Meetings by Telephone or Similar Communications Equipment.
Members of the board of directors or any committee designated by the board of
directors may participate in a meeting of the board of directors or any
committee by means of conference telephone or similar communications equipment
by means of which all persons participating in the meeting can hear each other,
and such participation in a meeting shall constitute presence in person at the
meeting.

     Section 10.  Compensation. Unless otherwise restricted by the certificate
of incorporation or these bylaws, the board of directors shall have the
authority to fix the compensation of directors. The directors and the Observers
shall be paid their reasonable out-of-pocket expenses, if any, incurred in
attending any meeting of the board of directors. Directors may also be paid a
fixed sum for attendance at each meeting of the board of directors or a stated
salary as director. No such payment shall preclude any director from serving the
corporation in any other capacity and receiving compensation therefor. Members
of special or standing committees may be allowed like compensation for attending
committee meetings.

     Section 11.  Removal of Directors. Unless otherwise restricted by statute,
the certificate of incorporation or any agreement among the shareholders, any
director or the entire board of directors may be removed, with or without cause,
by the holders of a majority of shares entitled to vote at an election of
directors.

     Section 12.  Resignation of Directors. Any director may resign at any time
by giving written notice to the board of directors, the chief executive officer
or the secretary of the corporation. Unless otherwise specified in such notice,
a resignation shall take effect upon the delivery thereof to the board of
directors or the designated officer. It shall not be necessary for a resignation
to be accepted before it becomes effective.

                                   ARTICLE IV

                                   COMMITTEES

     Section 1.   Designation. The board of directors may, by resolution passed
by a majority of the whole board, designate one (1) or more committees, each
committee to consist of one (1) or more of the directors of the corporation. The
board may designate one (1) or more directors as alternate members of any
committee, who may replace any absent or disqualified member at any meeting of
the committee.

                                       -4-

<PAGE>

               In the absence or disqualification of a member of a committee,
the member or members thereof present at any meeting and not disqualified from
voting, whether or not he or they constitute a quorum, may unanimously appoint
another member of the board of directors to act at the meeting in the place of
any such absent or disqualified member.

     Section 2.   Powers. Any such committee, to the extent provided in the
resolution of the board of directors, shall have and may exercise all the powers
and authority of the board of directors in the management of the business and
affairs of the corporation and may authorize the seal of the corporation to be
affixed to all papers which may require it; but no such committee shall have the
power or authority in reference to amending the certificate of incorporation
(except that a committee may, to the extent authorized in the resolution or
resolutions providing for the issuance of shares of stock adopted by the board
of directors as provided in Section 151(a) of the Delaware General Corporation
Law, fix any of the preferences or rights of such shares relating to dividends,
redemption, dissolution, any distribution of assets of the corporation or the
conversion into, or the exchange of such shares for, shares of any other class
or classes or any other series of the same or any other class or classes of
stock of the corporation), adopting an agreement of merger or consolidation,
recommending to the stockholders the sale, lease or exchange of all or
substantially all of the corporation's property and assets, recommending to the
stockholders a dissolution of the corporation or a revocation of a dissolution
or amending these bylaws; and, unless the resolution or the certificate of
incorporation expressly so provides, no such committee shall have the power or
authority to declare a dividend or to authorize the issuance of stock or to
adopt a certificate of ownership and merger. Such committee or committees shall
have such name or names as may be determined from time to time by resolution
adopted by the board of directors.

     Section 3.   Minutes and Reports. Each committee shall keep regular minutes
of its meetings and report the same to the board of directors when required.

                                    ARTICLE V

                                     NOTICES

     Section 1.   Form and Delivery. Whenever, under the provisions of statutes,
the certificate of incorporation or these bylaws, notice is required to be given
to any director or stockholder, it shall not be construed to mean personal
notice but such notice may be given in writing, by mail, addressed to such
director or stockholder at his address as it appears on the records of the
corporation, with postage thereon prepaid, and such notice shall be deemed to be
given at the time when the same shall be deposited in the United States mail.
Notice to directors may also be given by telegram, telex or facsimile
transmission at such director's address as it appears in the corporation's
records.

     Section 2.   Waiver. Whenever any notice is required to be given under the
provisions of statutes, the certificate of incorporation or these bylaws, a
waiver thereof in writing, signed by the person or persons entitled to said
notice, whether before or after the time stated therein, shall be deemed
equivalent to receipt of the notice.

                                       -5-

<PAGE>

     Section 3.   Attendance at Meetings as Waiver of Notice. Any stockholder
who attends a meeting of stockholders in person or is represented at that
meeting by proxy without protesting, at the commencement of the meeting, the
lack of notice to him or any director who attends a meeting of the board of
directors without protesting, at the commencement of the meeting, the lack of
notice to him shall, in each case, be conclusively deemed to have waived notice
of that meeting.

                                   ARTICLE VI

                                    OFFICERS

     Section 1.   Designation. The officers of the corporation shall be chosen
by the board of directors and shall be a chairman of the board, a president, a
chief executive officer, a treasurer and a secretary. The board of directors may
also choose one or more vice presidents and one or more assistant treasurers and
assistant secretaries. Any number of offices may be held by the same person,
unless the certificate of incorporation or these bylaws otherwise provide.

     Section 2.   Election. The board of directors at its annual meeting shall
choose a chairman of the board, a president, a chief executive officer, a
treasurer and a secretary and may choose such other officers as it deems
appropriate.

     Section 3.   Powers and Other Duties. The officers shall exercise such
powers and perform such duties as shall be determined from time to time by the
board of directors.

     Section 4.   Salaries. The salaries of all officers and agents of the
corporation shall be fixed by the board of directors.

     Section 5.   Term of and Removal from Office. The officers of the
corporation shall hold office until their successors are chosen and qualified.
Any officer elected or appointed by the board of directors may be removed at any
time by the affirmative vote of a majority of the board of directory Any vacancy
occurring in any office of the corporation shall be filled by the board of
directors.

     Section 6.   The Chairman of the Board. The chairman of the board of the
corporation shall preside at all meetings of the stockholders and the board of
directors and shall have such powers and perform such duties as may from time to
time be assigned by the board of directors, including, without limitation,
assisting the corporation with acquisitions.

     Section 7.   The Chief Executive Officer. The chief executive officer of
the corporation shall have the overall responsibility for, supervision of and
control over the day-to-day management of the business and operations of the
corporation, subject to the general policy directions of the board of directors,
and shall have such other powers and perform such other duties as may from time
to time be assigned to him by the board of directors.

                  The chief executive officer shall, under the seal of the
corporation, execute bonds, mortgages and other contracts requiring a seal
except where required or permitted by law to be otherwise signed and executed
and except where the signing and execution thereof shall be expressly delegated
by the board of directors to some other officer or agent of the corporation.

                                       -6-

<PAGE>

     Section 8.   The President. The president shall perform such duties and
have such powers as the board of directors may from time to time prescribe.

     Section 9.   The Treasurer. The treasurer shall have the custody of the
corporate funds and securities and shall keep full and accurate accounts of
receipts and disbursements in books belonging to the corporation and shall
deposit all moneys and other valuable effects in the name and to the credit of
the corporation in such depositories as may be designated by the board of
directors. The treasurer shall disburse the funds of the corporation as may be
ordered by the board of directors, taking proper vouchers for such
disbursements, and shall render to the president and the board of directors, at
its regular meetings or when the board of directors so requires, an account of
all the treasurer's transactions and of the financial condition of the
corporation.

                  If required by the board of directors, the treasurer shall
give the corporation a bond (which shall be renewed every six (6) years) in such
sum and with such surety or sureties as shall be satisfactory to the board of
directors for the faithful performance of the duties of the treasurer's office
and for the restoration to the corporation, in case of the treasurer's death,
resignation, retirement or removal from office, of all books, papers, vouchers,
money and other property of whatever kind in his possession or under the
treasurer's control belonging to the corporation.

     Section 10.  Vice Presidents. The vice presidents, if any, shall perform
such duties and have such powers as the board of directors may from time to time
prescribe.

     Section 11.  The Secretary. The secretary shall attend all meetings of the
board of directors and all meetings of the stockholders and record all the
proceedings of the meetings of the board of directors and of the stockholders in
a book to be kept for that purpose and shall perform like duties for the
standing committees when required. The secretary shall give, or cause to be
given, notice of all meetings of the stockholders and special meetings of the
board of directors and shall perform such other duties as may be prescribed by
the board of directors or the president, under whose supervision he shall be.
The secretary shall have custody of the corporate seal of the corporation and
the secretary or an assistant secretary shall have authority to affix the same
to any instrument requiring it and when so affixed, it may be attested by the
secretary's signature or by the signature of such assistant secretary. The board
of directors may give general authority to any other officer to affix the seal
of the corporation and to attest the affixing by the secretary's signature.

     Section 12.  The Assistant Treasurers and Secretaries. The assistant
treasurer and assistant secretary (or, if there is more than one, the assistant
treasurers and assistant Secretaries in the order designated by the board of
directors or, if there be no such designation, then in the order of their
election) shall, in the absence of the treasurer or secretary, or in the event
of the treasurer's or secretary's inability or refusal to act, perform the
duties and exercise the powers of the treasurer or secretary and shall perform
such other duties and have such other powers as the board of directors may from
time to time prescribe.

                                       -7-

<PAGE>

                                  ARTICLE VII

                             CERTIFICATES FOR SHARES

     Section 1.   Form and Signatures. The shares of the corporation shall be
represented by a certificate or shall be uncertificated. Certificates shall be
signed by, or in the name of the corporation by, the chief executive officer or
president and the treasurer or secretary or an assistant treasurer or assistant
secretary of the corporation.

             Upon the face or back of each stock certificate issued to represent
any partly paid shares, or upon the books and records of the corporation in the
case of uncertificated partly paid shares, shall be set forth the total amount
of the consideration to be paid therefor and the amount paid thereon shall be
stated.

             If the corporation shall be authorized to issue more than one (1)
class of stock or more than one (1) series of any class, the powers,
designations, preferences and relative, participating, optional or other special
rights of each class of stock or series thereof and the qualification,
limitations or restrictions of such preferences and/or rights shall be set forth
in full or summarized on the face or back of the certificate which the
corporation shall issue to represent such class or series of stock; provided
that, except as otherwise provided in Section 202 of the Delaware General
Corporation Law, in lieu of the foregoing requirements, there may be set forth
on the face or faces of the certificate which the corporation shall issue to
represent such class or series of stock a statement that the corporation will
furnish without charge to each stockholder who so requests the powers,
designations, preferences and relative, participating, optional or other special
rights of each class of stock or series thereof and the qualifications,
limitations or restrictions of such preferences and/or rights.

             Within a reasonable time after the issuance or transfer of
uncertificated stock, the corporation shall send to the registered owner thereof
a written notice containing the information required to be set forth or stated
on certificates pursuant to Sections 151, 156, 202(a) or 218(a) of the Delaware
General Corporation Law or a statement that the corporation will furnish without
charge to each stockholder who so requests the powers, designations, preferences
and relative, participating, optional or other special rights of each class of
stock or series thereof and the qualifications, limitations or restrictions of
such preferences and/or rights.

     Section 2.   Signature on Certificates. Any or all of the signatures on a
certificate may be facsimile. In case any officer, transfer agent or registrar
who has signed or whose facsimile signature has been placed upon a certificate
shall have ceased to be such officer, transfer agent or registrar before such
certificate is issued, it may be issued by the corporation with the same effect
as if he were such officer, transfer agent or registrar at the date of issue.

     Section 3.   Lost Certificates. The board of directors may direct a new
certificate or certificates or uncertificated shares to be issued in place of
any certificate or certificates therefore issued by the corporation alleged to
have been lost, stolen or destroyed. When authorizing such issue of a new
certificate or certificates or uncertificated shares, the board of directors may
require the owner or his legal representative to give the corporation a bond in
such sum as it may

                                       -8-

<PAGE>

direct as indemnity against the corporation with respect to the certificate
alleged to have been lost, stolen or destroyed.

     Section 4.   Transfers of Stock. Upon surrender to the corporation or the
transfer agent of the corporation of a certificate for shares duly endorsed or
accompanied by proper evidence of succession, assignation or authority to
transfer, it shall be the duty of the corporation to issue a new certificate to
the person entitled thereto, cancel the old certificate and record the
transaction upon its books. Upon receipt of proper transfer instruments from the
registered owner of uncertificated shares, such uncertificated shares shall be
canceled and issuance of new equivalent uncertificated shares or certificated
shares shall be made to the person entitled thereto and the transaction shall be
recorded upon the books of the corporation.

     Section 5.   Record Date. In order that the corporation may determine the
stockholders entitled to notice of or to vote at any meeting of stockholders or
any adjournment thereof, to express consent to corporate action in writing
without a meeting, to receive payment of any dividend or other distribution or
allotment of any rights, to exercise any rights in respect of any change,
conversion or exchange of stock or for the purpose of any other lawful action,
the board of directors may fix, in advance, a record date, which shall not be
more than sixty (60) nor less than ten (10) days before the date of such meeting
nor more than sixty (60) days prior to any other action. A determination of
stockholders of record entitled to notice of or to vote at a meeting of
stockholders shall apply to any adjournment of the meeting; provided, however,
that the board of directors may fix a new record date for the adjourned meeting.

     Section 6.   Registered Stockholders. The corporation shall be entitled to
recognize the exclusive right of a person registered on its books as the owner
of shares to receive dividends and to vote as such owner, and to hold liable for
calls and assessments a person registered on its books as the owner of shares,
and shall not be bound to recognize any equitable or other claim to or interest
in such share or shares on the part of any other person, whether or not it shall
have express or other notice thereof, except as otherwise provided by statute.

                                  ARTICLE VIII

                               GENERAL PROVISIONS

     Section 1.   Dividends. Dividends upon the outstanding capital stock of the
corporation, subject to the provisions of the statutes or the certificate of
incorporation, may be declared by the board of directors at any regular or
special meeting of directors and dividends may be paid in cash, property or in
shares of the capital stock.

     Section 2.   Reserves. Before payment of any dividend, there may be set
aside out of any funds of the corporation available for dividends such sum or
sums as the directors from time to time, in their absolute discretion, think
proper as a reserve or reserves to meet contingencies, for equalizing dividends,
for repairing or maintaining any property of the corporation or for such other
purpose as the directors shall think conducive to the interest of the
corporation and the directors may modify or abolish any such reserve in the
manner in which it was created.

                                       -9-

<PAGE>

     Section 3.   Annual Statement. The board of directors shall present at each
annual meeting or special meeting of the stockholders, when called for by vote
of the stockholders, a full and clear statement of the business and condition of
the corporation.

     Section 4.   Checks. All checks or demands for money and notes of the
corporation shall be signed by such officer or officers or such other person or
persons as the board of directors may from time to time designate.

     Section 5.   Fiscal Year. The fiscal year of the corporation shall be fixed
by resolution of the board of directors.

     Section 6.   Corporate Seal. The corporate seal shall have inscribed
thereon the name of the corporation, the year of its organization and the words
"Corporate Seal, Delaware". The seal may be used by causing it or a facsimile
thereof to be impressed, affixed, reproduced or otherwise.

     Section 7.   Indemnification. The corporation shall indemnify its officers
and directors to the fullest extent permitted by the General Corporation Law of
the State of Delaware. The Corporation may indemnify employees and agents of the
corporation in accordance with Delaware law as the board of directors shall
determine in its sole discretion.

                                   ARTICLE IX

                                   AMENDMENTS

               These bylaws may be altered, amended or repealed or new bylaws
may be adopted by the stockholders or by the board of directors, when such power
is conferred upon the board of directors by the certificate of incorporation, at
any regular meeting of the stockholders or of the board of directors or at any
special meeting of the stockholders or of the board of directors if notice of
such alteration, amendment, repeal or adoption of new bylaws is contained in the
notice of such special meeting. If the power to adopt, amend or repeal bylaws is
conferred upon the board of directors by the certificate of incorporation, it
shall not divest or limit the power of the stockholders to adopt, amend or
repeal bylaws.

                                       -10-