If you use Windows see iTunes for Windows: How to copy purchases between computers.
You can download items once when you purchase them from the iTunes Store. To use purchased items on a different computer, just copy the items and authorize that computer for your iTunes Store account. You can authorize up to five computers to use your purchased items.1 If you will no longer be using the computer you originally downloaded your purchases to, make sure to deauthorize that computer.
Once you've found the files for your purchased items, use any of the following methods to copy them to another computer. For information on where iTunes stores your audio files, see this article.
Burn a Data CD or DVD
Copy your purchased items to a data CD or DVD. See How to back up your media in iTunes to save purchased items onto a data disc that you can use with other authorized computers.
External hard drive
Drag files to the disk icon of an external hard drive connected to your computer. From there, you can copy them to other authorized computers. See Finding the files of your iTunes Store purchases for help locating items you purchased. You can also use many iPod models as a hard disk.
Use your iPod and iTunes
You can transfer iTunes Store purchases that are synced with your iPod to any authorized computer. For example, you can sync purchases from your home computer to your computer at work. For more details see iTunes Store: Transferring purchases from your iPhone, iPad, or iPod to your computer.
Other Removable Media
If you have an Iomega Zip or Jaz drive, or any other removable media that can be used by each computer, you can copy the songs to the removable disk and use the disk with other authorized computers. See Finding the files of your iTunes Store purchases for help locating song files you purchased.
- iTunes digital rights management (DRM) protected music includes audio with a bit rate of 128 kbps and allows users to transfer songs and videos to up to five computers, burn seven copies of the same playlist to CD, and sync to an unlimited number of iPods.
- iTunes Plus music refers to songs and music videos available in our highest-quality 256 kbps AAC encoding (twice the current bit rate of 128 kbps), and without digital rights management (DRM). There are no burn limits and iTunes Plus music will play on all iPods, Mac or Windows computers, Apple TVs, and many other digital music players.
- Purchases made from the App Store and iBooks Store can be re-downloaded for free as long as the app/book is still available for purchase.
A note about copyright
iTunes software may be used to reproduce materials. It is licensed to you only for reproduction of non-copyrighted materials, materials in which you own the copyright, or materials you are authorized or legally permitted to reproduce. If you are uncertain about your right to copy any material, you should contact your legal advisor. See the iTunes Store Terms of Service for additional information.