"To find your iPhone's UDID, just plug it into your computer and wait until iTunes recognizes it. Select your phone from the Devices list in iTunes and click the "Summary" tab. To see your UDID, click on the word "serial number" beside the picture of the iPhone. You should see the word "identifer" and an alphanumeric string – this is your UDID. "
Send that to the address in your email and that should do it.
Comments
http://www.tuaw.com/2008/08/08/iphone-101-find-udid-with-a-single-click/
"To find your iPhone's UDID, just plug it into your computer and wait until iTunes recognizes it. Select your phone from the Devices list in iTunes and click the "Summary" tab. To see your UDID, click on the word "serial number" beside the picture of the iPhone. You should see the word "identifer" and an alphanumeric string – this is your UDID. "
Send that to the address in your email and that should do it.