Office of the Law Revision Counsel - United States Code

The United States Code is a consolidation and codification by subject matter of the general and permanent laws of the United States. It is prepared by the Office of the Law Revision Counsel of the United States House of Representatives. 

This site has browse, basic and advanced search options with a "search tips" page for guidelines on constructing an effective search query.

It also has the Popular Name Table; Other Tables and Tools; Classification Tables; and Currency & Updating information. 

There are sections for "Understanding the Code" and "Positive Law Codification".

You can download each title in 4 different formats.

There are links to FDsys and Thomas.

This is a free comprehensive site for the United States Code.  The search functionality and all of the tools/tables make it a one-stop place for USC research.

Ernster, the Virtual Library Cat