Library of Congress Congress.gov site has detailed status information, with links to the text of amendments and the Congressional Record, beginning with the 101st Congress (1989-90). Basic status information is available beginning with the 93rd Congress (1973-74).
You can retrieve status information by such search options as: bill number; subject; key word; title; sponsor; status.
Lexis sources are available for the current Congress (see link below) and for prior Congresses beginning with the 101st (1989-90). Source names for prior congresses follow the pattern "Congressional Bill Tracking Reports - 101st Congress, Archive"
Use the Congressional Index, KF 49 .C6 Law Reference (earlier editions — from 1969 — in Law Compact Storage, lower level of the library).
Check the "Status of Senate Bills" section or the "Status of House Bills" section in the appropriate volume. A subject index is also available.
Call the Office of Legislative Information at 202-225-1772 with the bill number in question.