president pro tempore - A constitutionally recognized officer of the Senate who presides over the chamber in the absence of the vice president. The president pro tempore (or, "president for a time") is elected by the Senate and is, by custom, the senator of the majority party with the longest record of continuous service.
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.