I've been trying to do the same with my Palm TX and GooSync.com. I'm having issues with appointmnets shifting times, but once that's sorted it looks like a good solution. You also don't need to provide your google login info to them, only allow the service access to your calendar. posted by monkeymadness at 2:38 PM on January 10, 2007
Yep, GooSync, using SyncML. I use it with my SE Z610i, works perfectly.
GooSync is much more attractive now that they use the Google authentication proxy, instead of storing your Google account details. posted by snap, crackle and pop at 4:14 PM on January 10, 2007
Your question got me thinking, and I decided to try something I saw a while ago again, the scheduleworld.com site.
Right now I'm just using it to sync GoogleCalendar with Outlook (and Outlook with my PDA).
On the other hand if simple is the thing you're looking for, I've had some success with this google code software which is a direct over the air sync between gcal and Windows Mobile. No idea how well it deals with complex events, or duplicate edits (when you change an item at both ends between syncs) but it certainly works for simple syncs.
posted by monkeymadness at 2:38 PM on January 10, 2007