Here are some links (h/t: Enviropundit) for energy conservation tax incentives:
Simply Insulate: Tax info made easy. Major information for existing homes, data for new homes not present (the site claims that IRS regulations are not available yet).
Tax Incentives Assistance Project: Runs the gamut from new and existing residential to business to vehicles.
DSIRE: Database of State Incentives for Renewable Energy.
Department of Energy: the horse's mouth.
(Also added to the Reference Library)
Visits since 2006/05/11: