Here is a link to The Sierra Club’s Eco Friendly Insulation. While this is mainly basic information and tips, it’s a good starting place. It also includes links to other sites, both in the article and in some of the comments posted by readers.
It’s also worth it to check into any incentives for installing eco-friendly insulation. A good place to start would be with your insurance company. The state you live in may also provide incentives. Your utility company may as well.
As for products, one to consider is denim. Here is a site for Ulttratouch Denim Insulation.