Out of five people who expressed interest in testing my app, none seem willing to give me their iphone/ipod touch id.
It seems that this is a problem with the beta testing method required for iphone apps. People feel as if giving away their device id is a privacy/security risk.
Info on how beta testing works (see section on adding beta testers):
http://furbo.org/2008/08/06/beta-testing-on-iphone-20