iPhone: The Missing Manual, 2nd Edition

Authorizing Computers

When you create an account in iTunes (a requirement for having an iPhone), you automatically authorize that computer to play purchases from the iTunes Store. Authorization is Apple's way of making sure you don't go playing those music tracks on more than five computers, which would greatly displease the record companies.

You can copy your purchases onto a maximum of four other computers. To authorize each one to play music from your account, choose Store→Authorize Computer. (Don't worry; you just have to do this once per machine.)

When you've maxed out your limit and can't authorize any more computers, you may need to deauthorize one. On the computer you wish to demote, choose Store→Deauthorize Computer.

Note

Not all songs you buy from iTunes are copy-protected. The ones labeled as iTunes Plus songs ave slightly higher audio quality—and they're not copy-protected. You can play them on any player that recognizes AAC files.

Then again, you can't go nuts, uploading them all over the Internet. Your name and email address are embedded in the file and quite visible to anyone (including any Apple lawyer) who chooses the track, chooses File→Get Info, and clicks the Summary tab.