PolitiFact is a project of the St. Petersburg Times that examine statements by members of Congress, the president, cabinet secretaries, lobbyists, people who testify before Congress and anyone else who speaks up in Washington. They use graphic displays in the form of meters to show degrees of accuracy as well as provide more in-depth analysis of their findings.

Their most recent creation is the "Obameter" which is dedicated to tracking the promises and actions taken according to those promises of the president. They are reported as No Action, Stalled or In the Works and then determined whether they are Promise Kept, Compromise or Promise Broken.

FactCheck.org is a nonpartisan, nonprofit "consumer advocate" organization that monitors the media and political speech for factual accuracy. It is a project of the Annenberg Public Policy Center of the University of Pennsylvania to address public policy issues at the local, state and federal levels.

This is a very informative and useful site when trying to weed out the truth from the spin.  It is also a good place to check before basing one's argument on potentially false information.

The Center for Media and Democracy (CMD) publishes the online resource known as SourceWatch

It operates as a collaborative effort of  the people and  organizations that profile entities shaping the public agenda. Their goal is to identify the  "front groups, PR spinners, industry-friendly experts, industry-funded organizations, and think tanks trying to manipulate public opinion on behalf of corporations or government."

When siting particular sources of information, it is important to know the origin of the information being generated.  It is not unusual that much of the information that is made available to us, the general public, is created by a source with an particular agenda.  Data may be added or left out to strengthen the point and sway opinion.  SourceWatch is a useful tool in identifying these sources and any possible conflicts of interests that may be present in the information presented.

On the SourceWatch page, there is a entry field at the upper left of the page where source names can be entered.  Check out the other resources available as well.