Having heard that it was part of President Obama’s stimulus plan, I volunteered to look into weatherization programs for our community on behalf of the Ojai Valley Green Coalition.
A brief overview from the Department of Energy:

The Weatherization Assistance Program enables low-income families to permanently reduce their energy bills by making their homes more energy efficient. During the last 32 years, the U.S. Department of Energy ‘s (DOE) Weatherization Assistance Program has provided weatherization services to more than 6.2 million low-income families.
By reducing the energy bills of low-income families instead of offering aid, weatherization reduces dependency and liberates these funds for spending on more pressing family issues. On average, weatherization reduces heating bills by 32% and overall energy bills by about $350 per year at current prices. This spending, in turn, spurs low-income communities toward job growth and economic development.

Here’s some information from the California Department of Community Services and Development:

GENERAL INFORMATION
The U.S. Department of Energy Weatherization Assistance Program (DOE WAP) has long served as the core program for delivering energy conservation services to low-income Californians. The Weatherization Assistance Program reduces the heating and cooling costs for low-income families by improving the energy efficiency of their homes and ensuring their health and safety. Among low-income households, the program focuses on those with elderly residents, individuals with disabilities, and families with children.
ASSISTANCE TYPE
Free weatherization services are available to eligible applicants to improve the energy efficiency of homes. Energy saving services include measures such as attic insulation, caulking, water heater blanket, heating/cooling system repair, and other conservation measures.

Who is eligible? Renters and homeowners who qualify for the Low-Income Home Energy Assistance Program (LIHEAP) or Reduced Rate Programs (RRP):

Guidelines
Number of People Living in Household – total household income before taxes cannot exceed:
1 – $29,300
2 – $29,300
3 – $34,400
4 – $41,500
5 – $48,600
6 – $57,700
If greater than 6, add the following amount per person – $7,100

What to do if you qualify? You get in touch with Community Action of Ventura County – visit the website and click Weatherization in the left column. More information about CA-VC, including contact info, requirements, what documents you’ll need, etc., are available from the Department of Community Services and Development Energy Service Providers listing.
If you have anything to add, or any of this information doesn’t jive with what you are finding out, please contribute in the comments, and I’ll update the main post.