EXHIBIT A

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                                    EXHIBIT A

                                    AGREEMENT

                          JOINT FILING OF SCHEDULE 13G

                  The undersigned hereby agree to jointly prepare and file with
regulatory authorities a Schedule 13G and any future amendments thereto
reporting each of the undersigned's ownership of securities of U.S. Wireless
Data, Inc. and hereby affirm that such Schedule 13G is being filed on behalf of
each of the undersigned.


Dated:  January 14, 2002            /s/ Xxx X. Xxxxxxxx
                                    ---------------------
                                    Xxx X. Xxxxxxxx


Dated:  January 14, 2002   Corsair Capital Partners, L.P.

                                    By: /s/ Xxx X. Xxxxxxxx
                                        ---------------------
                                        Xxx X. Xxxxxxxx
                                        General Partner


Dated:  January 14, 2002   Corsair Capital Partners II, L.P.

                                    By: Corsair Managing Partners,
                                        General Partner

                                          By: Corsair Management Company, Inc.,
                                              a general partner

                                                By: /s/ Xxx X. Xxxxxxxx
                                                    ---------------------
                                                    Xxx X. Xxxxxxxx
                                                    President


Dated:  January 14, 2002   Corsair Management Company, Inc.

                                    By: /s/ Xxx X. Xxxxxxxx
                                        ---------------------
                                        Xxx X. Xxxxxxxx
                                        President


Dated:  January 14, 2002   Corsair Managing Partners

                                    By: Corsair Management Company, Inc.,
                                    a general partner

                                          By: /s/ Xxx X. Xxxxxxxx
                                              ---------------------
                                              Xxx X. Xxxxxxxx
                                              President