changing apple id on iphone

Note that downloaded content (apps, some music) are linked to the AppleID used to purchase them, so changing your AppleID can cause difficulties with that purchased content. If you only want to change your +email address+ you can keep the same AppleID (even though you're no longer using that email account). To change your email contact information, _do not_ change in iTunes on your computer. Instead, go to the site below and click on email to edit that information.

Should you want to change your AppleID anyway, you can also do that using the link below, or via iTunes on your computer.

http://myinfo.apple.com

You can do that, but you'll need to re-purchase those apps (and redownload the free ones, since those are also linked to the iTunes Store account used to download them).

Once you change the AppleID in iTunes, sync the phone - the iTunes login information used by the iPhone is taken from the active account in iTunes at the last sync.

Sign in to your store account in iTunes, then sync your phone.

http://support.apple.com/kb/HT1311
"When you sync your iPhone or iPod touch with your computer, the account last used to access the iTunes Store from the computer is synced to the mobile device for use in the iTunes Store from the device as well. This same account is used for the App Store as well. This account will be used on the device for both stores until you sign in from your computer to the iTunes Store with a different account, and then resync your mobile device with the computer."