I am now into the final few days of my visit to Washington DC. I shall have to get an iphone for my return to the UK! There are a number of "apps" which are available -

The Sunlight Foundation has just launched an application which gives

Live Floor Updates - Updates from the House and Senate floor as they happen.
Key Documents - Critical reports and memos as they are published online by the Congressional Budget Office, the Congressional Research Service, Office of Management and Budget, party policy committees and more!
Whip Notices - Daily and weekly notices from the House Majority and Minority Whips.
Hearing Schedules - Schedule of upcoming committee hearings from House and Senate.

C-Span has apps which allow you to listen to proceedings

and there is a Congressional Directory available called "Congress in Your Pocket"