A project of the Annenberg Public Policy Center of the University of Pennsylvania, it is a nonpartisan, nonprofit "consumer advocate" for voters that aims to reduce the level of deception and confusion in U.S. politics. It monitors “the factual accuracy of what is said by major U.S. political players in the form of TV ads, debates, speeches, interviews, and news releases.”
Annenberg Flack Check
This new Annenberg site fights fact-mangling site through humor and quick turnarounds without further propagating the underlying deception.
Columbia Journalism Review
The campaign desk site mission: “to encourage and stimulate excellence in journalism in the service of a free society. It is both a watchdog and a friend of the press in all its forms, from newspapers to magazines to radio, television, and the Web…CJR examines day-to-day press performance as well as the forces that affect that performance.”
Open Secrets
The site of The Center for Responsive Politics calls itself: "Your Guide to the Money in U.S. elections" – the “guide to money’s influence on U.S. elections and public policy.”
PolitiFact
PolitiFact is “A scorecard separating fact from fiction. A project of the St. Petersburg Times and Congressional Quarterly, it helps find the truth in the presidential campaign. “Every day, reporters and researchers from the Times and CQ will analyze the candidates' speeches, TV ads and interviews and determine whether the claims are accurate.”
Real Clear Politics
“An independent political site that culls and publishes the best commentary, news, polling data, and links to important resources.” Updated daily.
Snopes
A website for validating or debunking urban legends, Internet rumor, email hoaxes, and other such stories of uncertain or questionable origin.
Washington Post Fact Checker A permanent Post feature, it uses the one to four “Pinocchio” system to evaluate statements and claims.
Hat tip to Beverly Bandler for this fact check list