Farecast is a new Web 2.0 service to find best deals on US domestic (and eventually global) flights. From
TechCrunch:
Seattle-based Farecast, now in private beta, is an airfare pricing comparision tool that also uses a predictive algorithm to recommend when you buy your ticket. So the idea is to show the user not just who has the cheapest ticket, but whether or not waiting might make sense as well.
You can also read more about it
here.
If you are interested in an invitation (I have 20 of them), reply to this thread
and PM me your e-mail (if you post your e-mail here, it'll get spidered by nasty spam bots).