I wrote a post back in February about posting to FB, Twitter and Buzz all at once. Since then I've found a better way.
You're reading this because you have your reasons for posting to multiple site. Just a word of caution, don't post to more places than you can keep up with. Posting to Buzz and not being there to participate in the following discussion is worse than not posting at all in my opinion. Keep the "social" in social media.
On ping.fm click Add Network and add your GTalk status. You'll have to enter your GTalk/Gmail information.
Then go to Hootsuite. Add Ping.fm as a network.
Once you add your Twitter account and Facebook account you'll be able to post to all three or any of the three at once.
Hope this helps.