This looks like a very useful project! Microsoft has chosen not to support the open standard CalDAV (to their own disadvantage) and you have all stepped up to the challenge of adding support to Windows Mobile (WM) devices.
I assume that gmobilesync works by synchronising the WM Calendar events with Google Calendar's over CalDAV. This allows the events to be seen by WM's Calendar application.
A problem with Google Calendar is that it does not support VTODO items, which would be called "Tasks" in WM. I am a big user of VTODO items in iCal and would be very very happy to have up-to-date access to my VTODO list on the move.
Are there any future plans to:-
a) support other CalDAV servers? (e.g. free accounts available on hub.chandlerproject.org)
b) support for VTODO items (as WM Tasks)? (not supported by Google Calendar)
I have experience accessing CalDAV servers for VTODO items in Java, and would certainly be able to give pointers to you if you'd like to add this support. I'd offer to code it up myself, but I have no C#/.NET experience and I'm on Apple OS X (so no SDK
for WM). At any rate, they are almost the same as VEVENT.
If you intend to set up your own local CalDAV server, I'd strongly recommend DAViCAL (rscds.sourceforge.net) over the Cosmo server (chandlerproject.org/Developers/DownloadChandlerServer) as Cosmo is quite a pain to install, and very buggy. If you're on
Apple, then the obvious CalDAV server choice should be Darwin CalendarServer (calendarserver.org). Unfortunately, CalDAV servers are not yet as easy to install and maintain as they should be.