Image from Flickr by malias
Check out this article from the New York Times: 10 Ways to Cut Your Travel Costs This Year. They outline some great new resources you may not have thought of and suggest things like signing up for a Twitter account, using services like Yapta and Farecompare.com. Also included are other websites that will help you find the cheapest days to fly.
They also take a look the cost of home rentals vs. hotels and even taking the bus. Check it out, it is definitely worth the read!