On NETTUTS.com a tutorial has been posted recently showing you how to build a widget for Buzz, the Google's service similar to Twitter. If you've ever worked with the Twitter timeline concept, using Buzz will feel very familiar. Unfortunately, for the moment at least, it's a read-only kind of thing.
At the moment, there's no API to work with the Buzz service; Google is expected to provide one within the next several months, however, for now, the public updates are available as Atom feeds.
They grab these Atom feeds via a proxy PHP script (can't cross-domain with Ajax, after all) and then some Ajax to real the latest from this proxy. The results are displayed in a (very familiar looking) timeline with the help of the included HTML and CSS/images. The last part of the process is to push it into a jQuery plugin for easier use down the line. You can get the source download here and check out a demo online.