Q: como activar mi tarjeta itunes, como activar mi tarjeta itunes

iTunes Store: How to redeem a code - http://support.apple.com/kb/HT1574 - If you have an iTunes Gift Card or other code that you want to redeem in the iTunes Store. Includes hierarchy of how things are charged.

iTunes Store:  Invalid, Inactive, or Illegible codes - http://support.apple.com/kb/TS1292 - gift cards