Noise vs. News: What's Your Source?

A product of the Annenberg Public Policy Center, this site is terrific for checking up on political claims.

One of the oldest debunking sites on the Internet, Snopes.com focuses on urban legends, news stories and memes. the also cite their sources at the end of each debunking.

A professional networking website where you can look up the authors of articles and books to see if they're credible.

The Pulitzer Prize-winning Politifact researches the claims of politicians and checks their accuracy.

While focused primarily on political facts, it covers specific claims in-depth and with plenty of cross-referencing.