Now, there is a new bill (H.R. 5351, the Renewable Energy and Energy Conservation Tax Act of 2008) on the table which would not only extend all of the “set to expire†tax credits, but would improve almost all of them.
Residential Energy Efficiency Tax Credits

Renewable Energy And Energy Efficiency Tax Credits Are Back On The Table

Tell Congress to Extend Energy Efficiency Tax Incentives
Yesterday the Senate Finance Committee approved an economic stimulus package that includes one-year extensions of several energy-related tax incentives slated to expire at the end of 2008, including the energy efficient commercial building tax credit and tax incentives for purchasing energy efficient equipment...
"IRS Residential Tax Rebates Info" - from GoodCommonSense.net
You can quickly determine whether or not your energy efficient or fuel-efficient transportation investments qualify for 2007 tax credits, including Residential Energy Efficiency Tax Credits, Clean Energy Installations, Heating & Cooling Upgrades and Residential Transportation Efficiency Tax Credits