Spotted this page on Wired. Interesting info on when to buy.

Just thought I'd add it in, as the topic seems to come up quite regularly on the BBS

I work for an airline. The fare calculations are a nightmare. I'd say as a general rule for now, if the price of oil keeps going up, ticket prices will also go up. In the USA starting this fall most airlines are cutting routes and frequecies. This should translate into yet higher fares. The airline industry is hurting right now, don't look for things to turn around quickly.

That's awesome. Too bad his company was already purchased by Microsoft. They still have it available here.