United States Code (1994+) - "the codification by subject matter of the general and permanent laws of the United States. It is divided by broad subjects into 50 titles."
U.S. Code collection (Cornell University Law School) - "This version is generated from the most recent official version made available by the US House of Representatives."
Public Laws (1973+) - Thomas (Library of Congress) makes federal legislative information freely available to the public, including the text of bills and the Congressional Record.
Public & Private Laws (1995+) (GPO Access)
Code of Federal Regulations (1996+) - "the codification of the general and permanent rules published in the Federal Register by the executive departments and agencies of the Federal Government. It is divided into 50 titles that represent broad areas subject to Federal regulation."
Federal Register (1994+) "is the official daily publication for rules, proposed rules, and notices of Federal agencies and organizations, as well as executive orders and other presidential documents."