Congress joins the Web 2.0 world thanks to a bill pushed by some grass roots groups like this one and that one. There are Congressmen already using Twitter. They are listed here. You can watch them with this widget:
Now there is an open source microblogging service like Twitter called Identica. CNET has the interview with Identica. A further explanation about Identica and Laconia are here.
With all the buzz about Twitter, businesses have a platform for creating an internal app. I think people puke too much on Twitter. Try following some of these folks using Twitbin (a Firefox plug-in) and the page quickly fills with one person's messages. Ridiculous even if his name is Guy. I wonder how much puking Congress Critters will do -- or if they just tell their aides what to Tweet.