Like many people, I got the NeuevaSync email today.
I've just followed http://www.google.com/support/forum/...8dea5ed7&hl=en and it worked fine *without clearing the local N900 calender*.
I'm on a stock device with PR1.3.

A test event created sync'ed up OK, and when removed from Google Calender on their web site was removed when I did a 2nd manual sync.