I've started using Kayak.com's flight price alerts and just wanted to share with you guys. Basically, you create a username and password on Kayak.com (free) and you can have it track flight costs every day and send you an updated daily email with the lowest prices. For example, if I'm flying from JFK to MCO on November 30th, returning December 7th, I can plug those dates in and Kayak will send me a daily email with the cheapest prices along with a notation as to how much the prices have gone up or down since the day before.
I was watching one flight that was stuck at $427 for weeks, then suddenly dropped down to $199!!
Just wanted to share -- it's a good tool if you're trying to get a good deal on flights. 
