I have 25 Farecast invites available to anyone who is interested. Just drop me a note. I'll need your e-mail address to send the invite, so e-mail me at coder at wiredprairie.us. It's an airfare pricing comparison tool that uses a predictive algorithm of some sort to try to determine when the best time to buy airline tickets would be.

There's some more information at TechCrunch about Farecast.