1. A method of automatically updating calendar data for a plurality of users, the calendar data being associated with a calendar program executable by a personal digital assistant (PDA) with calendar data resident in a base computer system, comprising: (a) associating with updated and/or new calendar data in the base computer system with identification identifying an intended recipient of the data identified from the plurality of users; (b) transmitting, using a wireless broadcast system, the updated and/or new calendar data for reception and use by the PDA; and (c) the receiving the transmitted updated and/or new calendar data and updating the calendar data associated with the calendar program executable by the PDA.