Travel planning service Yapta has a cool new feature for registered users that lets you track price drops or award seats based on your frequent-flier mileage. It'll keep an eye out for deals that match how many miles you have saved up, and give you an alert when they're up for grabs. When used properly this system could net you free or heavily discounted tickets alongside letting you know about potential price drops.
In addition to tracking single seats, you can have it track deals on several seats on the same flight. This works for any number of seats, and can get you deals you might not see with single-seat searches.
Currently the program supports frequent-flier programs from five airlines, including Alaska, Continental, Delta, US Airways, and United. Notably missing are Southwest and JetBlue's rewards programs, however the two may be added later down the line.
Also worth mentioning is that Yapta does not currently give you the heads-up on any service or redemption fees that can be incurred when using frequent-flier miles toward a discounted flight.