If your law practice involves dealing with the U.S. Congress, you will want to read two recent reviews of the Congress in Your Pocket apps by Cohen Research Group. The company sells three apps. Congress is $0.99 and gives you basic information about every member of Congress. Congress+ is $9.99 and adds staff information, committee assignments and one free update of the database in 2010. CongressPro is $99.99 and the database in that version is updated throughout the year. (And if you practice in California, the developer also has California in Your Pocket apps.)
Congress+ was recently reviewed by Macworld. The reviewer liked the app, giving it a 4 out of 5 mouse rating and saying that the app is "indispensable" for those interested in Congress because of its "extensive database packed with information on congressional leaders,
their staffers, committee activities and the minutiae of the
legislative process."
The website Apple iPhone Apps also recently reviewed Congress+ and also gave it a 4 out of 5 review, concluding that the app is "very well done app in function and form, contains loads of information (contact or otherwise), and appears to has a responsive development team (based on user comments) and my own experience."
Older reviews of Congress+ can be found at AppCraver and AppleStoreApps.
I haven't tested the app myself as I don't do governmental relations work, but it might be worth checking out if you do. Here are a few screenshots from the app provided by the developer, and if you want more you should look at this page from the developer's web site containing 45 screen shots.
Click here to get Congress ($0.99): 
Click here to get Congress+ ($9.99):
Click here to get CongressPro ($99.99):
