Redeem your Membership Card on your computer:
1. From Xbox.com, use your Windows LIVE ID to sign in to your Xbox LIVE account.
2. Select My Account from the My Xbox drop-down menu.
3. Click Redeem Code to enter the pre-paid code for the content that you want to redeem.
4. Follow the instructions that appear on the screen to enter and confirm the redemption on the pre-paid code.

Redeem on your Xbox Console:
1. Sign into Xbox LIVE.
2. Click the Xbox Guide button located in the center of the controller.
3. Navigate to the Marketplace tab. Select Redeem Code.
4. Enter your 25 digit pre-paid code and enjoy!