The first place to start in reducing your energy use has always been an energy audit. CWLP, which has long offered such audits, appears to have just revamped them a little bit by adding a money-back guarantee. This isn't your regular money-back guarantee, though. After CWLP comes out, does a blower door test, and walks through your house showing you what you can do, if you do any of the recommended actions and bring them back in to check your work, you can get the $25 cost of the audit refunded, along with up to $25 in expenses for some of those retrofits.
Not only that, if you don't know the business end of a caulking gun, you can attend a low-cost/no-cost energy efficiency workshop (which covers most of the things you'll probably hear about when you get an audit)--the next one is November 3.