FedWorld.gov - Access to federal government information
GovTrack - Information on federal legislation, voting records, and campaign contributions.
FDSYS Federal Digital System - Official access point to information published by the federal government
Library of Congress - Information about and research from the Library of Congress
Regulations.gov - access to regulations currently open for public comment
Statistical Abstracts of the United States - Archives - Wide variety of national statistical information
Thomas: Legislative Information on the Internet - Congressional information from 1990 - present