Tw2buzz pulls your contact list on Twitter right into Google Buzz to match them to Google accounts. You can then decide if you want to follow them. Happily it is not automatic as Google Buzz started and gives you the chance to choose. Of course, they chose the proper path of using oAuth, so a good beginning.
It is currently in closed beta, but you can request an account on the webpage. A bulk follow ability is in the works but the Google API does not have that ability yet.