Looking up information on Congress? There's an app for that.

Several applications about the legislative branch are available for the iPhone, Apple's popular mobile phone. (One app is available for Google's Android platform ; none on the BlackBerry.)

The iPhone apps vary in quality of information and ease of use, however.

The Cohen Research Group offers three versions of its helpful Congress app, which allows you to look up Members by chamber or state.

* The basic version costs 99 cents and includes the contact information, biographical details and Web site links for every Member of the 111th Congress.

* The premium version, called Congress+, costs $4.99 and includes staff contact information, maps of Congressional districts, links to each lawmaker’s recent legislative activity and easy access to campaign finance reports.

* The professional version, called CongressPro, costs $29.99 and adds significantly more detail on committee and subcommittee staff.

For lobbyists and full-time advocates, the premium or professional versions are necessary to find more detailed information. Most political junkies will find the basic version meets their needs, however.

The information on all three versions was fairly up-to-date, including the staff of recently appointed Sen. Paul Kirk (D) of Massachusetts.

One downside is that the Congress+ version of the application is prone to crashing and is slow to start.

Two major competitors for the Congress apps are iCongress and Congress Members, both priced at 99 cents.

Komitt Technologies' iCongress has a difficult-to-use interface and offers scant information about each Member, and its search function is tedious. The app also incorrectly listed the late Sen. Edward Kennedy (D-Mass.).

Ole Gammelgaard Poulsen's Congress Members app was also disappointing.

The interface was an improvement over iCongress, but the app failed to take advantage of the iPhone's interface, simply sending users to each Member's page on Wikipedia.

The free My Government app developed by Jeremy Andrus is actually an improvement over both iCongress and Congress Members.

The app uses the iPhone's features well, using the internal GPS to determine the user's local legislators. Though it lacks any biographical information, it offers users the option of calling, e-mailing or tweeting each lawmaker.

In addition, it features a directory of bills under consideration with links to the full text, the sponsors and the ability to tweet about the bill as well as a community message board for users.

The program suffers from slow load times in some menus, however.

(Full Disclosure: The CQ-Roll Call Group, corporate parent of Congress.org, also publishes Congressional directories through its Congressional Quarterly and Knowlegis divisions.)

Byron Tau writes for Roll Call.