Q: They will eventually release the iPhone 5 and I am planning on getting one. In the mean time I want to rename my iPhone 3G so that when I get my new phone I can still add games and other apps to my old phone and use it like an iPod touch. I know how to rename my device using iTunes. My question is, does changing the name on the phone cause iTunes to do anything to the things already stored on the phone? In other words, will it do a restore to factory settings so that I have to start over? Or does it really just change the name of the device?
A: The short answer is that it really just changes the name of the device. Nothing more and nothing less.
The actual name of the iPhone is mostly meaningless and is used primarily for display purposes in iTunes. With the addition of Personal Hotspot in iOS 4.3 it also becomes your default wireless network name. Beyond that, however, it doesn’t really matter what you call your iPhone. Internally, each iPhone has a Unique Device Identifier (UDID) that cannot normally be changed. This UDID is how iTunes keeps track of your specific iPhone in terms of sync settings and backups. Some third-party apps that store device-specific user profiles can also use the UDID for this purpose.
Note that content purchased from the iTunes Store, whether it be applications or media content, is not associated even with your UDID, much less your device’s name. The only thing that matters for this is your iTunes Store account, which becomes associated with your device either by loading on purchased content through iTunes, or logging into the iTunes or App Store on your device.