Apple has just released Airport Utility for iOS (Free, App Store Link) – an app designed to configure and manage AirPort wireless devices (such as the Time Capsule, AirPort Express and AirPort Extreme) from a local network. Prior rumors suggested that it would be released as an App Store app, and Apple has now made that official.
It’s important to note that Airport Utility does require iOS 5 to run, which Apple hasn’t released yet, so unless you have the GM, you’ll need to wait. You can, however, download it ahead of time in iTunes (Free, App Store Link), just so you’re ready when the moment arrives.