Those of you who have ever had an occasion to beta test a not-yet-released app will be familiar with the term UDID. It’s a 40-character string that serves as a unique identifier for a device.
You can see an iPhone, or iPad’s – UDID in iTunes when the device is connected via USB, by clicking on the string next to the Serial Number label on the main Info page for the device.
UDIDIt is a handy little free app that lets you see your UDID right on the iPhone itself, and gives you a one-tap option to email the number to a developer or other party who may need to know the UDID.
I’ve tested the app on my iPad and it works fine. Good to know.