A great resource for current rebates is DSIRE (Database of State Incentives for Renewables and Efficiency).
Here are a few more links to get you started.
Connecticut
Energize CT
Norwich Public Utilities
Maine
Efficiency Maine
Massachusetts
Mass Save
New Hampshire
Unitil
New Hampshire Saves
New Jersey
New Jersey Clean Energy
New York
Central Hudson
National Fuel
National Grid
Rhode Island
National Grid
Vermont
Efficiency Vermont
Vermont Gas