Federal Acquisition Regulations
Contains the complete United States Federal Acquisition Regulations, which can be downloaded into a Word "Document Indexed" file

FedBizOpps [formerly Commerce Business Daily (BIDNET)]
Federal government bid notices and awards

Contracting Opportunities - GSA Mid-Atlantic Region
Federal government bid notices and awards

General Services Administration Federal Government Index
Links to many useful government and miscellaneous sites

US Army Corp of Engineers
This site contain topics of interest for contractors doing federal work