Instructions
Go to Xbox.com and click on the "Join Xbox Live" tab at the top of the homepage.
View the list of services on the next page. Silver memberships also offer avatar creation and voice and text chat, while Gold members can stream Netflix to their consoles and use Facebook and Twitter on their Xbox 360 systems.
Choose the free or paid service and click the appropriate tab. Enter your email address on the next page.
Fill out the user information in the boxes on the following page. Here you can create your gamertag and pick a picture to represent you. (Once you access your gamertag on your Xbox 360 console, you can create an avatar.) Accept the terms of agreement to complete your application.
Enter your credit card information on the next page if you choose a Gold membership to begin your paid service.