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.