http://support.apple.com/kb/HT2737?viewlocale=en_US
Summary
iTunes gift certificates can be used to purchase movies, TV shows, music and music videos, as well as audiobooks from the iTunes Store. This article will explain how to redeem iTunes Store Gift Certificates. To learn about how to redeem iTunes Store Gift Cards, refer to iTunes Store: How to redeem an iTunes Gift Card.
iTunes gift certificates cannot be used for online Apple Store purchases. Gift certificates can only be used in the same online store where purchased and can not be transferred to a different country or other region online stores.
Note: Some features or services are not available in some iTunes Store countries.
Products Affected
iTunes Store
- Download and install the latest version of iTunes
- Open iTunes, from your Desktop or Start Menu in Windows, or from your Dock or Applications folder in Mac OS X.
- In the Sources list, click on the iTunes Store.
- In the right-hand column of the iTunes Store, click the Redeem link.
At the Redemption page, carefully enter in your iTunes Store Gift Certificate code.
If you do not already have an iTunes Store account, you will be asked to create one after correctly entering in your iTunes Store gift certificate. A credit card is not required to set up an account if you followed these instructions.