If your iPhone is running OS 3.0 or higher and you're suffering from constant dropped calls, poor network performance, and the like, then AT&T's "Mark the Spot" may be for you. Launched to provide "the best network experience possible," the application allows AT&T users to report dropped calls, failed calls, data failure, no coverage (I guess you would have to wait until you returned to a coverage area), and more. Users can submit a real-time report capturing GPS coordinates, or can wait and submit a report at a later time.
User reports will be sent to AT&T, and a text message will inform them that their report was received. No word on whether a BlackBerry or Windows Mobile version will launch in the future, but considering a vast majority of their data-centric users are on iPhones, the priority makes sense. Who wants to be a network tester for AT&T?