Instructions
Visit the "My LIVE account was suspended" board on the Xbox forums (link in Resources).
Click "Sign In" at the top of the page and log in to your Live account.
Press "New Post."
Type a title in the "Subject" line asking about your suspension.
Enter any further questions or appeals you have in the "Description" box. Make sure to include the name of the gamertag with the suspension somewhere in the message.
Click "Post." You will not see your message appear because all messages on the forum must go through manual approval. Do not re-post your message.
Scroll to the bottom of the forum page and click "Settings."
Check the "Receive Emails" box in your settings and click "Save." A Microsoft employee may reply to your post via email, and without this option selected you won't get the message.
Wait for a reply from Microsoft or wait for your suspension period to run its course.