List of Free code UIDevice
Add functionality to UIDevice to distinguish between platforms like iPod touch 1G and 2G and iPhone.
UIDevice MacAddress Helper
Find Mac address on iOS device and create UDID from that MAC address.
A simple, handy UIDevice category that makes checking system version easy in iOS apps.
UIDevice with UniqueIdentifier for iOS 5
Brings back the unique identifier support under iOS 5, it uses the device's mac address in combination with the bundle identifier to generate a new hashed unique identifier.