iOS 7 How-to: Redeem iTunes gift cards with your device’s camera
iTunes gift cards are a great gift for iOS Device users. They can be used to purchase content from the iTunes Store, App Store, and iBookstore. However, entering in the string of characters to redeem the gift card balance has typically been a pain with the touch keyboards on iPads, iPhone, and iPod touches. Like iTunes 11 on the Mac, iOS 7 moves to solve this problem. You can now use your device’s camera to scan in the code.
Go to the main/featured page in whichever store you choose and to get to the redemption screen, scroll all the way down, and press on redeem: