Not that redeeming a gift card was ever difficult but, in iTunes 11, is gets a little easier. Instead of entering the code manually, you can now use the camera to capture it.
STEP 1: Click on ‘iTunes Store’.
STEP 2: Click on ‘Redeem’.
STEP 3: Enter your Apple ID password.
STEP 4: Click on ‘Use Camera’.
STEP 5: Remove the sticker on the back of the gift card to reveal the code. Hold the back of your iTunes gift card up to the camera until you see the black box around the code. If there is an issue with the gift card code (such as it has already been registered), you will be notified under the black box.
STEP 6: Success!!
Obviously, this is not a mind-boggling feature of iTunes 11. Just a nice little feature that makes redeeming a gift card a little easier.