title: How to detect the same user in different iPhones?
body: <p>We're building an iPhone app which should store some info in a server.</p>
  
  <p>We were planning to use the iPhone ID to store this info, but we've come across a problem: if the user switches from his iPhone 3Gs to the new iPhone 4G, the iPhone ID will naturally change, but the user is still the same.</p>
  
  <p>Is there a way, from the iPhone app, to detect some sort of user ID rather than the iPhone ID, so we hold to that when saving the info in the server?</p>
  
  <p>Note: we could indeed do a register/login mechanism, so when the user logs in the proper info is pulled from the server, but we were thinking that if we can do without the login that'd be awesome.</p>
  
  <p>Thanks!</p>