I played around a good while ago with opensync from the daily GPE package repository trying to sync GPE on the tablet with the calendar on the phone (Nokia 6120 S60 3rd edition btw) and did not have much luck. This was with the intention to sync the phone to outlook, then GPE on the tablet to the phone, as google calendar access is severely restricted at work.

I've now got a blackberry 8800 from work, so do not need this functionality to work any more, but all the packages have been updated since then.

http://www.cobb.uk.net/770/ is a good place to start, as graham has some command line scripts on there which could be used as a starting point.

Hope this helps

Gaz