The first step to getting your free Xbox live membership is to sign up to the rewards website. After making a username, password, and email address, you have to activate your account. You do this by clicking the link that is sent to your email address. Once you do this, 250 points (worth $2.50) will be deposited into your account.
The next step is to accumulate enough points and/or cash to get your free Xbox live membership. There are many ways to earn points or cash, such as: filling out short surveys, playing games, and referring other people to the rewards website, via your referral link. Click here to learn more about how to earn points and cash.
The final Step is to order your free Xbox live membership. Once you have earned enough points or cash to order your reward, click on the "Spend Points" tab on the rewards website. It usually takes a few days for your order to be approved. As far as the Xbox live memberships go, you can get a 12 month, 3 month, or a 1 month live membership.
Xbox Live memberships are just one of the many items you can get using this website. You could also get Xbox 360 games, equipment, Microsoft Points, and the actual Xbox 360 console if you choose.