Here’s a list of links to various think tanks

American Dream Coalition American Enterprise Institute/Environmental Policy
American Legislative Exchange Council Carbon Dioxide Information Analysis Center
Cato Institute Center for Science and Public Policy
Centre for Resource Management Studies CO2 Science
Competitive Enterprise Institute George Marshall Institute
GreenWatch.org Heartland Institute
Heritage Foundation Institute for Energy Research
The John Locke Foundation JunkScience.com
Natural Resources Stewardship Project The New Zealand Climate Science Coalition
Property and Environment Research Center Reason Foundation/Air Quality and Climate
Science and Environmental Policy Project

Global Warming Heartland Institute

Thoreau Institute
The Independent Institute