The first tool to show your (public) Buzz post is your profile page.
And this page is "RSS enabled", in the sense that one can subscribe to any individual Buzz flow in any "RSS feed" reader, such as Google Reader. (URL style: http://profiles.google.com/[BuzzID] )
If your reader does not translate the profile url correctly or if you want to play directly with the raw data through the API, you can use http://buzz.googleapis.com/feeds/[BuzzID]/public/posted .
All informations about the Buzz API is in Google code.
Then, with the same feature, you can use another Google product, FeedBurner, to push your Buzz posts in multiple formats to multiple destinations, including Twitter. (more info soon)
Last, there are a few 3rd party tools to push or interact your Buzz with other Social Networks.
Sadly, those services are not always very reliable, but we're on internet, ain't we?
For many social networks: (Twitter, Facebook, Tumblr, LinkedIn, MySpace & Buzz)