Congressional Budget Office - provides the Congress with the objective, timely, nonpartisan analyses needed for economic and budget decisions.
Center on Budget and Policy Priorities - conducts nonpartisan research and analysis on a range of government policies and programs, with an emphasis on those affecting low- and moderate-income people.
Citizens Against Government Waste - dedicated to elimination of waste, fraud, and abuse in the federal government. Site includes the 2002 Pig Book, which examines pork barrel spending.