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                                                                   EXHIBIT 10.18

                              EMPLOYMENT AGREEMENT

       THIS AGREEMENT is entered into as of the 18th day of September, 2000
(the "Effective Date"), by and between Donald Listwin (the "Executive") and
Phone.com, Inc., a Delaware corporation (the "Corporation").

       For ease of reference, this Agreement is divided into the following
parts:


FIRST PART:   TERM OF EMPLOYMENT, DUTIES AND SCOPE, COMPENSATION AND BENEFITS
              DURING EMPLOYMENT


SECOND PART:  COMPENSATION AND BENEFITS IN CASE OF INVOLUNTARY TERMINATION


THIRD PART:   COMPENSATION AND BENEFITS IN CASE OF A CHANGE IN CONTROL


FOURTH PART:  PARACHUTE PAYMENTS, CONFIDENTIAL INFORMATION, SUCCESSORS,
              MISCELLANEOUS PROVISIONS, SIGNATURE PAGE
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FIRST PART:   TERM OF EMPLOYMENT, DUTIES AND SCOPE, COMPENSATION AND BENEFITS
              DURING EMPLOYMENT

Section 1.  Term of Employment
------------------------------

(a)  At-Will.  Subject to the terms and conditions of this Agreement,
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     Executive's employment with the Corporation is "at will" and Executive or
     the Corporation are free to terminate the employment relationship at any
     time, with or without Cause upon at least thirty (30) days written notice.

(b)  Termination for Cause.  The Corporation may terminate the Executive's
     ---------------------
     employment at any time for Cause.  For all purposes under this Agreement,
     "Cause" shall mean (1) a willful failure by the Executive to substantially
     perform the Executive's duties under this Agreement, other than a failure
     resulting from the Executive's complete or partial incapacity due to
     physical or mental illness or impairment, (2) a willful act by the
     Executive that constitutes gross misconduct and that is materially
     injurious to the Corporation, (3) a willful breach by the Executive of a
     material provision of this Agreement, (4) a material and willful violation
     of a federal or state law or regulation applicable to the business of the
     Corporation that is materially and demonstrably injurious to the
     Corporation, or (5) a material failure to achieve such reasonable financial
     and other performance measures as shall be agreed upon by the Compensation
     Committee of the Board of Directors and the Executive; all as determined by
     the Compensation Committee of the Board of Directors in good faith;
     provided, however, that failure of the parties to reasonably agree to such
     performance measures shall not be grounds for termination for cause.__No
     act, or failure to act, by the Executive shall be considered "willful"
     unless committed without good faith and without a reasonable belief that
     the act or omission was in the Corporation's best interest.

(c)  Termination for Disability.  The Corporation may terminate the Executive's
     --------------------------
     employment for Disability by giving the Executive not less than thirty-(30)
     day's advance written notice.  For all purposes under this Agreement,
     "Disability" shall mean that the Executive, at the time the notice is
     given, has been unable to perform the Executive's duties under this
     Agreement for a period of not less than six (6) consecutive months as a
     result of the Executive's incapacity due to physical or mental illness.  In
     the event that the Executive resumes the performance of substantially all
     of the Executive's duties under this Agreement before the termination of
     the Executive's employment under this Section 1 becomes effective, the
     notice of termination shall automatically be deemed to have been revoked.

(d)  Termination of Agreement.  This Agreement shall expire when all obligations
     of the parties hereunder have been satisfied.
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Section 2.  Duties and Scope of Employment
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(a)  Position.  The Corporation agrees to employ the Executive in the positions
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     of President and Chief Executive Officer ("PCEO").  Executive shall be
     given such duties, responsibilities and authorities as are appropriate to
     his position.  Executive shall also serve as a Director on the
     Corporation's Board of Directors (the "Board").

(b)  Obligations.  During the Agreement, the Executive shall devote the
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     Executive's full business efforts and time to the business and affairs of
     the Corporation as needed to carry out his duties and responsibilities
     hereunder subject to the overall supervision of the Board.  The foregoing
     shall not preclude the Executive from engaging in appropriate civic,
     charitable or religious activities or from devoting a reasonable amount of
     time to private investments or from serving on the boards of directors of
     other entities, as long as such activities and service do not interfere or
     conflict with the Executive's responsibilities to the Corporation.

Section 3.  Base Compensation
-----------------------------

During the Agreement, the Corporation agrees to pay the Executive as
compensation for services a base salary at the annual rate of $250,000, or at
such higher rate as the Compensation Committee of the Board may determine from
time to time.  Such salary shall be payable in accordance with the standard
payroll procedures of the Corporation. The annual compensation specified in this
Section 3, together with any increases in such compensation that the
Compensation Committee of the Board may grant from time to time, is referred to
in this Agreement as "Base Compensation."

Section 4.  Incentive Compensation
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During the Agreement, the Corporation shall award the Executive annual incentive
compensation ("Incentive Compensation") based upon a target which shall be at
least 50% of the Base Compensation, with the actual annual incentive award
determined in accordance with the achievement of financial and other performance
measures.  Executive shall also have the opportunity to earn two (2) times the
annual target based upon attainment of objectives defined by the Compensation
Committee. A minimum bonus equal to at least the target bonus shall be
guaranteed and paid in full as soon as practicable after the end of fiscal year
2001.  Any compensation paid to the Executive as Incentive Compensation shall be
in addition to the Base Compensation.  The Compensation Committee of the Board
will review the Executive's Incentive Compensation annually to ensure that the
target remains competitive.

Section 5.  Equity Compensation
-------------------------------

(a)  Stock Options.  Executive will be granted six (6) million stock options to
     -------------
     purchase the Corporation's common stock in accordance with the terms and
     conditions of the applicable stock option agreements associated therewith.
     The per share exercise price for such options shall be the closing trading
     price on the Effective Date.  Such options shall
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     vest as to twenty-five percent (25%) of the options on the first
     anniversary of the Effective Date and ratably thereafter at the rate of
     1/48 of such option award per month.

(b)  Other Equity Awards.  The Executive shall be considered for awards under
     -------------------
     the Corporation's existing and any new compensation and benefit plans in
     order to ensure that Executive's long-term incentives are competitive.

Section 6.  Executive Benefits
------------------------------

During the Agreement, the Executive shall be eligible to participate in all
employee and executive benefit plans and executive compensation programs
maintained by the Corporation, including (without limitation) savings or profit-
sharing plans, deferred compensation plans, stock option, incentive or other
bonus plans, life, disability, health, accident and other insurance programs,
and similar plans or programs.  Executive shall also be covered under the
Corporation's standard director and officer insurance and indemnification
programs.

Section 7.  Business Expenses and Travel
----------------------------------------

While rendering services to the Corporation, the Executive is authorized to
incur and shall be reimbursed for all necessary and reasonable travel,
entertainment and other business expenses.

Section 8.  Death or Disability
-------------------------------

If Executive's employment with the Corporation is terminated at any time due to
death or Disability, Executive shall receive (a) one (1) year of health
coverage, comparable to that provided to other senior executives of the
Corporation, for himself (if termination was due to Disability) and his family
and (b) continuance of life insurance coverage on his life for one (1) year
following termination (if termination was due to Disability).  To the extent
that the Corporation finds it undesirable to cover the Executive under the group
life insurance and health plans of the Corporation, the Corporation shall
provide the Executive (at its own expense) with the same level of coverage under
individual policies.
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SECOND PART:  COMPENSATION AND BENEFITS IN CASE OF INVOLUNTARY TERMINATION

Section 9.  Terminations
------------------------

This Second Part of the Agreement, consisting of Sections 9 through 10,
describes the benefits and compensation, if any, payable in case of a Qualifying
Termination of employment.  The Third Part of the Agreement, consisting of
Sections 11 and 12, describes benefits and compensation, if any, payable in case
of a Change in Control.

Section 10.  Termination Without Cause; Involuntary Termination
---------------------------------------------------------------

In the event that, during the Agreement, the Executive's employment terminates
in a Qualifying Termination, as defined in Section 10(a), then, after executing
the release of claims described in Section 10(c), the Executive shall be
entitled to receive the payments and benefits described in Section 8 and Section
10(b).

(a)  Qualifying Termination.  A Qualifying Termination occurs if:
     ----------------------

     (1)  The Corporation terminates the Executive's employment for any reason
          other than Cause, Death or Disability; or

     (2)  The Executive experiences an Involuntary Termination not resulting
          from a Change in Control.  For purposes of this Agreement, Involuntary
          Termination shall mean the occurrence of any of the following without
          the Executive's prior written consent:  (i) a greater than 10%
          reduction in Executive's base compensation, incentive compensation
          target and benefits except if a majority of the Board of Directors
          vote to reduce the salary of the Executive and the rest of the
          Corporation's executive officers by the same percentage amount for the
          same time period, (ii) a material change in Executive's status or his
          responsibilities (excluding loss of title as President of the
          Corporation), (iii) the Corporation's failure to continue Executive as
          its CEO, (iv) the Corporation's failure to nominate Executive for re-
          election as a member of the Board of Directors (unless Executive's
          employment is terminated for Cause), (v) if Executive is not at all
          times the Chief Executive Officer of the Corporation's ultimate parent
          entity (if any), or (vi) a requirement to relocate, except for office
          relocations that would not increase the Executive's one-way commute
          distance by more than thirty (30) miles.  For purposes of greater
          clarity, termination for Cause, death or Disability shall not give
          rise to an Involuntary Termination.

(b)  Payments and Benefits.  The Corporation shall pay to the Executive
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     following the date of termination of employment the following aggregate
     payments and benefits spread ratably over the succeeding twelve (12)
     months, in accordance with standard payroll procedures:

     (1)  One (1) times the Executive's Base Compensation in effect on the date
          of the termination of employment;
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     (2)  One (1) times the Executive's target Incentive Compensation for the
          year in which Executive's employment is terminated;

     (3)  50% of Executive's then unvested stock options shall become vested and
          Executive shall have one (1) year after the date of Qualifying
          Termination to exercise all vested options and Executive's remaining
          unvested options, if any, shall not expire until the earlier of (i)
          their original expiration date or (ii) one (1) year after the date of
          Qualifying Termination; and

     (4)  The same level of health and life insurance coverage provided under
          Section 8 above.  This coverage will be provided for one (1) year
          after termination of employment with COBRA benefits to begin
          thereafter.  The obligation of the Corporation to provide continued
          health and life insurance benefits under this Section 10 shall cease
          if Executive becomes employed by another employer and such employer
          provides the Executive with life insurance and health plan coverage
          that is comparable to the coverage contemplated by this Section 10.

(c)  Release of Claims.  As a condition to the receipt of the payments and
     -----------------
     benefits described in this Section 10, the Executive shall be required to
     execute a release of all claims arising out of the Executive's employment
     or the termination thereof including, but not limited to, any claim of
     discrimination under state or federal law, but excluding claims for
     indemnification from the Corporation under any indemnification agreement
     with the Corporation, its certificate of incorporation and by-laws or
     applicable law or claims for directors and officers' insurance coverage.

(d)  Conditions to Receipt of Payments and Benefits.  In view of Executive's
     ----------------------------------------------
     position and his access to Confidential Information, as a condition to the
     receipt of cash payments and health and life insurance benefits described
     in this Section 10, the Executive shall not, without the Corporation's
     written consent, directly or indirectly, alone or as a partner, joint
     venturer, officer, director, Executive, consultant, agent or stockholder
     (other than a less than 5% stockholder of a publicly traded company) (i)
     engage in any activity which is in competition with the business, the
     products or services of the Corporation (a list of competitors and
     competitive products and services, which may be updated, is attached
     hereto), (ii) solicit any of the Corporation's Executives, consultants or
     customers, (iii) hire any of the Corporation's Executives or consultants in
     an unlawful manner or actively encourage Executives or consultants to leave
     the Corporation, or (iv) otherwise breach his Confidential Information
     obligations.

(e)  No Mitigation.  Except as provided in Section 10(b)(4), the Executive shall
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     not be required to mitigate the amount of any payment or benefit
     contemplated by this Section 10, nor shall any such payment or benefit be
     reduced by any earnings or benefits that the Executive may receive from any
     other source.
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THIRD PART:  COMPENSATION AND BENEFITS IN CASE OF A CHANGE IN CONTROL

Section 11.  Change in Control
------------------------------

(a)  If Executive is still employed by the Corporation and there is a Change in
     Control, 50% of Executive's then unvested stock options shall become
     vested.  His remaining unvested stock options shall continue to vest at the
     same rate of vesting as before the Change in Control subject to Section
     11(b) below.

(b)  If a Qualifying Termination occurs in connection with a Change in Control
     or within eighteen (18) months after a Change in Control, the Executive
     will receive a cash severance payment equal to one (1) times the sum of his
     Base Compensation and target Incentive Compensation less any severance
     payments previously made under Section 10(b) above.  Such severance will be
     paid in a lump sum within ten (10) days of the Qualifying Termination.
     Executive shall receive the same health and life insurance benefits
     provided in Section 8.  Additionally, all of Executive's unvested stock
     options, if any, shall vest in full and Executive shall have one (1) year
     after the date of Qualifying Termination to exercise his vested options.

Section 12.  Definition of Change in Control
--------------------------------------------

For all purposes under this Agreement, "Change in Control" shall be as defined
below.

          (i) The stockholders of the Corporation approve an agreement for the
sale of all or substantially all of the assets of the Corporation to a person or
entity; or

          (ii) The stockholders of the Corporation approve a merger or
consolidation of the Corporation with any other corporation, other than a merger
or consolidation which would result in the voting securities of the Corporation
outstanding immediately prior thereto continuing to represent (either by
remaining outstanding or by being converted into voting securities of the
surviving entity) at least fifty percent (50%) of the total voting power
represented by the voting securities of the Corporation or such surviving entity
outstanding immediately after such merger or consolidation;

          (iii)  Completion of a tender or exchange offer or other transaction
or series of transactions by a person or entity that results in less than a
majority of the outstanding voting shares of the surviving corporation being
held, immediately after such transaction or series of transactions, by the
holders of the voting shares of the Corporation outstanding immediately prior to
such transaction or series of transactions.

     Notwithstanding the foregoing, a "Change in Control" shall not be deemed to
have occurred by virtue of the consummation of any transaction or series of
integrated transactions (i) immediately following which the record holders of
the common stock of the Corporation immediately prior to such transaction or
series of transactions continue to have substantially the

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same proportionate ownership in an entity which owns all or substantially all of
the assets of the Corporation immediately following such transaction or series
of transactions or (ii) involving the proposed merger between the Corporation
and Software.com, Inc.; or

               (iv)  Approval by the stockholders of the Corporation of a
          complete liquidation or dissolution of the Corporation.

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<PAGE>

FOURTH PART:  PARACHUTE PAYMENTS, CONFIDENTIAL INFORMATION, SUCCESSORS,
               MISCELLANEOUS PROVISIONS, SIGNATURE PAGE

Section 13.  Parachute Payments
-------------------------------

     In the event that the severance and other benefits provided for in this
Agreement or otherwise payable to the Executive (i) constitute "parachute
payments" within the meaning of Section 280G of the Internal Revenue Code of
1986, as amended (the "Code"), and (ii) but for this Section 13, would be
subject to the excise tax imposed by Section 4999 of the Code (or any
corresponding provisions of state income tax law), then the Executive's
severance benefits under Section 11 shall be either

          (a)  delivered in full, or

          (b) delivered as to such lesser extent which would result in no
portion of such severance benefits being subject to excise tax under Section
4999 of the Code, whichever of the foregoing amounts, taking into account the
applicable federal, state and local income taxes and the excise tax imposed by
Section 4999, results in the receipt by the Executive on an after-tax-basis, of
the greater amount of severance benefits, notwithstanding that all or some
portion of such severance benefits may be taxable under Section 4999 of the
Code.  Unless the Corporation and the Executive otherwise agree in writing, any
determination required under this Section 13 shall be made in writing by the
Corporation's accountants, whose determination shall be conclusive and binding
upon the Executive and the Corporation for all purposes.  For purposes of making
the calculations required by this Section 13, the accountants may make
reasonable assumptions and approximations concerning applicable taxes and may
rely on reasonable, good faith interpretations concerning the application of
Sections 280G and 4999 of the Code.  The Corporation and the Executive shall
furnish to the accountants such information and documents as the accountants may
reasonably request in order to make a determination under this Section 13.  The
Corporation shall bear all costs the accountants may reasonably incur in
connection with any calculations contemplated by this Section 13.  In the event
that subsection (a) above applies, then Executive shall be responsible for any
excise taxes imposed with respect to such severance and other benefits.  In the
event that subsection (b) above applies, then each benefit provided hereunder
shall be proportionately reduced to the extent necessary to avoid imposition of
such excise taxes.

Section 14.  Confidential Information
-------------------------------------

The Corporation and the Executive will enter into the Corporation's standard
Employee Inventions and Assignment Agreement which shall govern use by the
Executive of the Corporation's confidential information.

Section 15.  Successors
-----------------------

(a)  Corporation's Successors.  The Corporation shall require any successor
     ------------------------
     (whether direct or indirect and whether by purchase, lease, merger,
     consolidation, liquidation or otherwise)

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<PAGE>

     to all or substantially all of the Corporation's business and/or assets, by
     an agreement in substance and form satisfactory to the Executive, to assume
     this Agreement and to agree expressly to perform this Agreement in the same
     manner and to the same extent as the Corporation would be required to
     perform it in the absence of a succession. The Corporation's failure to
     obtain such agreement prior to the effectiveness of a succession shall be a
     breach of this Agreement and shall entitle the Executive to all of the
     compensation and benefits to which the Executive would have been entitled
     hereunder if the Corporation had involuntarily terminated the Executive's
     employment without Cause or Disability, on the date when such succession
     becomes effective. For all purposes under this Agreement, the term
     "Corporation" shall include any successor to the Corporation's business
     and/or assets that executes and delivers the assumption agreement described
     in this Section 15(a) or that becomes bound by this Agreement by operation
     of law.

(b)  Executive's Successors.  This Agreement and all rights of the Executive
     ----------------------
     hereunder shall inure to the benefit of, and be enforceable by, the
     Executive's personal or legal representatives, executors, administrators,
     successors, heirs, distributees, devisees and legatees.

Section 16.  Miscellaneous Provisions
-------------------------------------

(a)  Waiver.  No provision of this Agreement shall be modified, waived or
     ------
     discharged unless the modification, waiver or discharge is agreed to in
     writing and signed by the Executive and by an authorized officer of the
     Corporation (other than the Executive).  No waiver by either party of any
     breach of, or of compliance with, any condition or provision of this
     Agreement by the other party shall be considered a waiver of any other
     condition or provision or of the same condition or provision at another
     time.

(b)  Whole Agreement.  No agreements, representations or understandings (whether
     ---------------
     oral or written and whether express or implied) that are not expressly set
     forth in this Agreement have been made or entered into by either party with
     respect to the subject matter hereof.  In addition, the Executive hereby
     acknowledges and agrees that this Agreement, the stock option agreements
     referenced above, and the Employee Inventions and Assignment Agreement
     supersede in their entirety any agreements between the Executive and the
     Corporation in effect immediately prior to the effective date of this
     Agreement.  As of the Effective Date, any such agreement shall terminate
     without any further obligation by either party thereto, and the Executive
     hereby relinquishes any further rights that the Executive may have had
     under any such prior agreement.

(c)  Notice.  Notices and all other communications contemplated by this
     ------
     Agreement shall be in writing and shall be deemed to have been duly given
     when personally delivered or when mailed by U.S. registered or certified
     mail, return receipt requested and postage prepaid.  In the case of the
     Executive, mailed notices shall be addressed to the Executive at the home
     address that the Executive most recently communicated to the Corporation in

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<PAGE>

     writing.  In the case of the Corporation, mailed notices shall be addressed
     to its corporate headquarters, and all notices shall be directed to the
     attention of the Board.

(d)  No Setoff.  Except as provided in Section 10, there shall be no right of
     ---------
     setoff or counterclaim, with respect to any claim, debt or obligation,
     against payments to the Executive under this Agreement.

(e)  Choice of Law.  The validity, interpretation, construction and performance
     -------------
     of this Agreement shall be governed by the laws of the State of California,
     irrespective of California's choice-of-law principles.

(f)  Severability.  The invalidity or unenforceability of any provision or
     ------------
     provisions of this Agreement shall not affect the validity or
     enforceability of any other provision hereof, which shall remain in full
     force and effect.

(g)  Arbitration.  Except as otherwise provided in Section 13 and in the
     -----------
     enforcement of Section 14, any dispute or controversy arising out of the
     Executive's employment or the termination thereof, including, but not
     limited to, any claim of discrimination under state or federal law, shall
     be settled exclusively by arbitration in Palo Alto, California, in
     accordance with the rules of the American Arbitration Association then in
     effect.  Judgment may be entered on the arbitrator's award in any court
     having jurisdiction.

(h)  No Assignment of Benefits.  The rights of any person to payments or
     -------------------------
     benefits under this Agreement shall not be made subject to option or
     assignment, either by voluntary or involuntary assignment or by operation
     of law, including (without limitation) bankruptcy, garnishment, attachment
     or other creditor's process, and any action in violation of this Section
     16(h) shall be void.

(i)  Limitation of Remedies.  If the Executive's employment terminates for any
     ----------------------
     reason, the Executive shall not be entitled to any payments, benefits,
     damages, awards or compensation other than as provided by this Agreement.

(j)  Employment Taxes.  All payments made pursuant to this Agreement shall be
     ----------------
     subject to withholding of applicable taxes.

(k)  Benefit Coverage Non-Additive.  In the event that the Executive is entitled
     -----------------------------
     to life insurance and health plan coverage under more than one provision
     hereunder, only one provision shall apply, and neither the periods of
     coverage nor the amounts of benefits shall be additive.

(l)  Discharge of Responsibility. The payments under this Agreement, when made
     ---------------------------
     in accordance with the terms of this Agreement shall fully discharge all
     responsibilities of the Corporation to the Executive that existed at the
     time of termination of the Executive's employment.

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<PAGE>

(m)  Attorney and Consultant Fees.  The Corporation will pay for all reasonable
     ----------------------------
     fees incurred in connection with the negotiation and preparation of this
     Agreement.

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<PAGE>

IN WITNESS WHEREOF, each of the parties has executed this Agreement, in the case
------------------
of the Corporation by its duly authorized officer, as of the day and year first
above written.


                                     EXECUTIVE



                                             /s/ Donald Listwin
                                     -------------------------------------------
                                                 Donald Listwin



                                     PHONE.COM, INC.


                                     By    /s/ Alain Rossmann
                                        ---------------------------------------

                                     Its    Chairman
                                         --------------------------------------

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