As mentioned before, iCal export is only available for Leopard (OS 10.5) users. I use some "plug-in" code for the calendar export stuff, and the maker of it assures me the windows export (which will actually be a .ics file) will be ready in the next few weeks. Once that is done, support for Google/Yahoo calendar, Outlook and iCal (Tiger and before) should be there.

Email me if you have questions : [email protected]