Signed into law on February 17, 2009 by President Obama, this bill contains an "existing homes energy efficiency tax credit." This program is run by the Department of Energy, who is responsible for providing the funding and technical guidance to the states. However, each state runs their own programs and sets the rules for issues such as eligibility. The individual states select the contractors and review the work for quality control.

Weatherization includes the following:

Insulation
Air sealing
Window replacement
HVAC replacement
Water heater replacement
Etc.
To find out more about the program, go to: http://apps1.eere.energy.gov/weatherization/

The DOE says, "Adding insulation is part of almost every weatherization project." To find out more about adding insulation to your existing home, go to: http://apps1.eere.energy.gov/weatherization/wxtech_insulation.cfm

For information about how to apply for the tax credit, please go to:
http://www.energystar.gov/index.cfm?c=products.pr_tax_credits#1