I am not aware WinXP has a reminder utility but the freeware, Windows
Scheduler, has. Though I've only used this reminder once while
concentrating on its other more general Windows task scheduling, it appears
to be as good as one could possibly wish for in this sort of tool, and it is
easy to set up too. If I remember correctly, at the pre-set time an alert
with your own chosen words pops up together with a honk. Now, if that can
be synchronized with your PDA or mobile.... http://www.splinterware.com/products/wincron.htm