If you haven't got an account yet - just sign up at http://twitter.com/. I've had an account for a long time now - but have recently started to use "Tweetdeck" as a platform that allows me to have my screen updated regularly with "Tweets" from individuals and bodies I follow - as well as updates of my friends' status on Facebook. I can also "tweet" direct to Twitter and Facebook. To download TweetDeck go to http://tweetdeck.com/beta/download/.
My favourite sources of news are :-
US Congress
CQPolitics - Excellent & Frequent Tweeter on Congress. Well Respected Publisher on Congress
RollCall - my favourite newspaper available in DC (and by subscription even in Milton Keynes)
thehill - from "The Hill" a newspaper about Congress
CSPAN - the cable channel providing live coverage of Congress - and much much more
Senatus - coverage of US Senate
OpenCRS - access to some of the excellent reports produced by the first class CRS
Senator Reid - Majority Leader of the Senate
NancyPelosi - unofficial site, news of the Speaker of the House of Representatives
Johnboehner - Minority Leader, House of Representatives
UK Parliament
UK Parliament - from the Palace of Westminster direct
Politics_co_uk - good UK based news service
Epolitix - another good news service specialising in Parliamentary matters
Hansard Society - from that excellent Society (see many previous posts)
Downing Street - from No 10
I'd welcome any of your recommendations. (If you want to link up with me on facebook - my name their is 'jdavidmorgan'. I also use Skype - with the same name.)