EPAct 2005 - The Energy Policy Act of 2005 contains many provisions to promote the research, production, and use of renewable energy. Tax Credit Extensions Summary Table - 110th Congress extended many provisions of EPAct.
DSIRE 
- Database of State Incentives for Renewable Energy is a comprehensive source of information on state, local, utility, and selected federal incentives that promote renewable energy.
State Energy Efficiency Tax Credits - Summary table from 2008 General Assembly (HB2 - bill index)
Contact your local utility - they frequently offer energy audits and rebates or other incentives for energy efficiency.