For those who are looking for just calendar sync, Lorelai is working on an app called Erminig which does two way multiple calendar syncing for Google. The nice thing about that app is that you can sync to multiple calendars on the N900 unlike the nuevasync solution. I believe he is working on scripts to do timed sync as well as an expansion to do contact sync as well.
more here....

http://talk.maemo.org/showthread.php?t=40408