act - Legislation (a bill or joint resolution, see below) which has passed both chambers of Congress in identical form, been signed into law by the president, or passed over his veto, thus becoming law. Technically, this term also refers to a bill that has been passed by one house and engrossed (prepared as an official copy).
Congressional Sessions lists all Congresses and corresponding years - from 1789, when the 1st Congress met, through the current Congress.
You can access legislative information, by bill number or key words, from the THOMAS Web site. Information from the present back to the 93rd Congress (1973) is available on THOMAS.
For information on the Senate, Congress, the legislative process and the federal government, the Virtual Reference Desk is a good place to begin.