Airport Utility Manager

The free AirPort Utility manager from Apple lets you control your Wi-Fi network and AirPort base stations, including AirPort Express, AirPort Extreme, and Time Capsule, right from your iPhone. When you launch the app, you'll see a picture representation of your network and devices. It'll tell you what's connected to what and how. You can change the network and Wi-Fi settings, start or restore a base station, access networking information (like DNS server, router address, IP address), and more.