Like Southwest's Ding! and Expedia's Fare Alert before it, American Airlines now has its own free downloadable desktop tool, DealFinder. Essentially an add-on to American's site that allows you to personalize your experience, DealFinder is a useful application for AAdvantage members and those who fly American extensively.
DealFinder is much like Fare Alert, in that you tell the tool what you want (e.g. a $300 flight from New York to Los Angeles) and a pop-up will alert you when a fare matches the parameters you've set. Just enter your desired route, number of travelers, dates of travel, and desired fare, and the tool will continually search for the deal you want. You can save itineraries, so you're able to have multiple searches occurring simultaneously. Unfortunately, as far as I could tell, there is no flexible-date search; you have to enter specific departure and destination dates. A flexible-search option would allow those without set schedules to potentially find even lower fares because they wouldn't be limited by the days they'd chosen.
American also allows you to sign up for customized email offers and promotions when you install DealFinder, or even place a "deal ticker" at the top of your screen. I'm happy to report that you can just as easily stay off those lists and turn off that feature if you want. However, if you're one of American's most frequent flyers, these aspects of DealFinder may be appealing. Overall, it's those American Airlines loyalists who will really benefit from this tool, since it obviously only searches American's fares. For the rest of us, as always, shopping around will still yield the best prices.