You can find out your device’s UDID using iTunes 7.7. or later. To do this, connect your device to your Mac or PC and launch iTunes. In iTunes, select your device in the ‘Devices’ section and navigate to the Summary tab. Click on the Serial Number label to reveal the Identifier field and the 40 character UDID. Press Command+C (Ctrl+C) to copy the UDID to your clipboard.