Here's some Advice from JCitunescards.com on How to redeem your Gift Card on iTunes Store USA.
Follow our step by step instructions to Set Up your iTunes account without a Credit card, redeem the code or change the store location.
1. Start iTunes on your Mac or PC.
2. Select the iTunes store from the left window pane.
3. Log out of your current iTunes Store if logged in, using the log out link on the far right of the iTunes menu bar.
4. Scroll down to the bottom of the page and select Change Country from the iTunes Settings. Choose United States.
5. Find the Quick Links box, on the upper right side in main iTunes window.
6. Select the Redeem link.
7. Type or paste in your code and click the redeem button.
8. Set up the account with an email address that has not been registered with any other iTunes store.
9. Use an existing US address including corresponding zip code. Just use any hotel or business address.
If asked for payment method select none. Do NOT enter your Credit Card details.
Enjoy!
