Research Guides:

Federal Legislative History [pdf]
Federal Statutory Research [pdf]
Using LexisNexis Congressional to Find Federal Legislative Materials [pdf]

Databases:

HeinOnline
Libraries include: US Statutes at Large; U.S. Congressional Documents, Session Laws with varying coverage for the 50 states; the Congressional Record and debates; Nancy P. Johnson’s Sources of Compiled Legislative Histories; and US Federal Legislative History Title Collection.

LexisNexis Congressional
Can search by keyword or citation for Legislative Histories (1969-present); Congressional Reports (1819-present); Congressional Hearings (published and unpublished) (1824-present); Congressional Committee Prints (1830-present); U.S. Congressional Serial Set and American State Papers from 1789-1969; and CRS Reports (1916-present). Also contains member biographies, committee assignments, voting records, and financial data.

LLMC Digital
The world's largest digital collection of legal literature and federal executive, legislative, and judicial branch documents in microform format.  The collection includes statutes,  administrative decisions and reports of government agencies, boards, and departments. The current emphasis is mainly on historical documents (1790-2000).