Climate Science
Climate Change 101, Pew Center on Climate Change. Provides a basic tutorial on the science of global warming.

How to Talk to a Climate Change Skeptic. Gives a very thorough breakdown of common misunderstandings and myths about global warming.

The Scientific Evidence. Woods Hole Research Center. Provides a more detailed perspective of climate science.

Intergovernmental Panel on Climate Change fourth assessment report.  The latest synthesis of research by hundreds of scientists representing several national academies of science.

http://www.realclimate.org – A commentary site by working climate scientists for the interested public and journalists. They aim to provide a quick response to developing stories and provide the context sometimes missing in mainstream commentary.

http://dels-old.nas.edu/climatechange/ - The National Academies provides helpful analysis and advice to policymakers and stakeholders through its expert, consensus reports and other activities. The reports are produced by committees of the nation’s top scientists, engineers, and other experts who are convened to address key scientific and technical aspects of climate change and other topics.

Climate Policy
Hoosier Environmental Council Policy Paper on Climate Policy and Cap and Trade. A comprehensive analysis, with a focus on Indiana, of the American Clean Energy and Security Act, which was passed by the U.S. House in June 2009.

U.S. Environmental Protection Agency analysis. Economic analysis of the impact of the American Clean Energy and Security Act on the U.S. economy.