Document:

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                                                                     Exhibit 4.2

                       INTERACTIVE SYSTEMS WORLDWIDE INC.
                           2 ANDREWS DRIVE (2ND FLOOR)
                             WEST PATERSON, NJ 07424

                                                              September 6, 2005

Omicron Master Trust
c/o Omicron Capital L.P.
650 5th Ave, 24th Floor
New York, NY 10019
Attn:  Brian Daly

Midsummer Investment, Ltd.
c/o Midsummer Capital, LLC
485 Madison Avenue, 23rd Floor
New York, NY  10022
Attn:  Scott Kaufman

Iroquois Master Fund Ltd.
641 Lexington Ave.
New York, NY  10022
Attn: Richard Abbe

Gentlemen:

         Reference is made to the Certificate of Designation of Preferences,
Rights And Limitations of Series C 6% Convertible Preferred Stock of Interactive
Systems Worldwide Inc. ("ISW"), as filed with the Secretary of State of the
State of Delaware on August 8, 2005 (the "COD"), and the Warrants, dated August
3, 2005 held by each of you (the "Warrants"). All capitalized terms used herein
and not otherwise defined shall have the meanings ascribed to them in the COD or
Warrants, as applicable.

         1. By executing the applicable signature line below and returning this
letter to ISW you hereby consent to amending each of the COD and the Warrant
held by you, all as set forth in Exhibit A hereto.

         2. This amendment by letter agreement may be executed in two or more
counterparts, all of which when taken together shall be considered one and the
same agreement and shall become effective when counterparts have been signed by
each of the parties and delivered to the other parties, it being understood that
the parties need not sign the same counterpart. In the event that any signature
is delivered by facsimile transmission, such signature shall create a valid and
binding obligation of the party executing (or on whose behalf such signature is
executed) with the same force and effect as if such facsimile signature page
were an original thereof.

<PAGE>

                                            Sincerely,

                                            INTERACTIVE SYSTEMS WORLDWIDE INC.

                                            By: /s/ Bernard Albanese
                                                ------------------------
                                            Name:  Bernard Albanese
                                            Title: President

ACKNOWLEDGED AND AGREED BY

OMICRON MASTER TRUST

By: /s/ Bruce Bernstein
    -----------------------
Name:  Bruce Bernstein
Title: Managing Partner

ACKNOWLEDGED AND AGREED BY

MIDSUMMER INVESTMENT LTD.

By: /s/ Scott D. Kaufman
    -----------------------
Name:  Scott D. Kaufman
Title: Managing Director

ACKNOWLEDGED AND AGREED BY

IROQUOIS MASTER FUND LTD.

By: /s/ Richard Abbe
    --------------------
Name:  Richard Abbe
Title: Director

<PAGE>

                                    EXHIBIT A

1.  The COD is hereby amended as follows:

    a. In Section 6(c), the following language is hereby deleted:

              "The provisions of this Section 6(b) [sic] may be waived by any
              Holder upon, at the election of such Holder, not less than 61
              days' prior notice to the Corporation, and the provisions of this
              Section 6(b) [sic] shall continue to apply until such 61st day (or
              such later date, as determined by such Holder, as may be specified
              in such notice of waiver)."

    b. In Section 6(d), the following language is hereby deleted:

              "or such greater number of shares of Common Stock permitted
              pursuant to the corporate governance rules of the Nasdaq SmallCap
              Market or such other exchange or market, that is at the time the
              principal trading exchange or market for the Common Stock,"

2.  Each of the Warrants is hereby amended as follows:

    a. In Section 3(c), the following language is hereby deleted:

              "The provisions of this Section 3(c) may be waived by the Holder
              upon, at the election of the Holder, not less than 61 days' prior
              notice to the Company, and the provisions of this Section 3(c)
              shall continue to apply until such 61st day (or such later date,
              as determined by the Holder, as may be specified in such notice of
              waiver)."

    b.  Section 3.1(c) is hereby renumbered as Section 3.1(c)(i), and the
        following language is hereby inserted as a new Section 3.1(c)(ii):

              "Unless the Company first obtains Shareholder Approval, the
              Company may not issue upon exercise of this Warrant, a number of
              shares of Common Stock, which, when, aggregated with any shares of
              Common Stock issued prior to such exercise date (A) upon
              conversion of or as payment of dividends on the Preferred Stock
              and (B) upon exercise of any of the warrants issued pursuant to
              the Purchase Agreement, would exceed 19.999% of the number of
              shares of Common Stock outstanding on the Trading Day immediately
              preceding August 3, 2005, based upon share volume, as confirmed in
              writing by counsel to the Company (the "Maximum Aggregate Share
              Amount"). Each Holder of Warrants issued on the date hereof shall
              be entitled to a portion of the Maximum Aggregate Share Amount
              equal to the quotient obtained by dividing (x) the number of
              shares of Common Stock into which this Warrant is exercisable by
              (y) the aggregate number of shares into which all of the Warrants
              issued on the date hereof are exercisable. Such portions shall be
              adjusted upward ratably in the event all of the Warrants are no
              longer outstanding."

         All other terms and conditions of the COD and the Warrants not
specifically modified herein remain in full force and effect as contained in the
COD or Warrants, as applicable.<PAGE>

                                                                     Exhibit 4.3

                       INTERACTIVE SYSTEMS WORLDWIDE INC.
                           2 ANDREWS DRIVE (2ND FLOOR)
                             WEST PATERSON, NJ 07424

                                                              September 6, 2005

Brandon Ross
315 E. 86th Street, Apt 8DE
New York, NY 10028

Gentlemen:

         Reference is made to the Interactive Systems Worldwide Inc. ("ISW")
Warrant, dated August 3, 2005, held by you (the "Warrant"). All capitalized
terms used herein and not otherwise defined shall have the meanings ascribed to
them in the Warrant.

         1. By executing the applicable signature line below and returning this
letter to ISW you hereby consent to amending the Warrant as set forth in Exhibit
A hereto.

         2. This amendment by letter agreement may be executed in two or more
counterparts, all of which when taken together shall be considered one and the
same agreement and shall become effective when counterparts have been signed by
each of the parties and delivered to the other parties, it being understood that
the parties need not sign the same counterpart. In the event that any signature
is delivered by facsimile transmission, such signature shall create a valid and
binding obligation of the party executing (or on whose behalf such signature is
executed) with the same force and effect as if such facsimile signature page
were an original thereof.

                                            Sincerely,

                                            INTERACTIVE SYSTEMS WORLDWIDE INC.

                                            By: /s/ Bernard Albanese
                                                ------------------------
                                            Name:  Bernard Albanese
                                            Title: President

ACKNOWLEDGED AND AGREED BY

/s/ Brandon Ross
-----------------------------
Brandon Ross

<PAGE>

                                    EXHIBIT A

1.    The Warrant is hereby amended as follows:

      a. In Section 3(c), the following language is hereby deleted:

                "The provisions of this Section 3(c) may be waived by the Holder
                upon, at the election of the Holder, not less than 61 days'
                prior notice to the Company, and the provisions of this Section
                3(c) shall continue to apply until such 61st day (or such later
                date, as determined by the Holder, as may be specified in such
                notice of waiver)."

      b. Section 3.1(c) is hereby renumbered as Section 3.1(c)(i), and the
         following language is hereby inserted as a new Section 3.1(c)(ii):

                "Unless the Company first obtains Shareholder Approval, the
                Company may not issue upon exercise of this Warrant, a number of
                shares of Common Stock, which, when, aggregated with any shares
                of Common Stock issued prior to such exercise date (A) upon
                conversion of or as payment of dividends on the Preferred Stock
                and (B) upon exercise of any of the warrants issued pursuant to
                the Purchase Agreement, would exceed 19.999% of the number of
                shares of Common Stock outstanding on the Trading Day
                immediately preceding August 3, 2005, based upon share volume,
                as confirmed in writing by counsel to the Company (the "Maximum
                Aggregate Share Amount"). Each Holder of Warrants issued on the
                date hereof shall be entitled to a portion of the Maximum
                Aggregate Share Amount equal to the quotient obtained by
                dividing (x) the number of shares of Common Stock into which
                this Warrant is exercisable by (y) the aggregate number of
                shares into which all of the Warrants issued on the date hereof
                are exercisable. Such portions shall be adjusted upward ratably
                in the event all of the Warrants are no longer outstanding."

         All other terms and conditions of the Warrant not specifically modified
herein remain in full force and effect as contained in the Warrant.

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