http://www.xbox.com/en-US/myxbox/features-gamercards.htm

If you have live and have a .net passport. Sign up. Everything is explained right there.

For you lazy folks:
My Xbox is a seamless integration between Xbox 360, Xbox Live®, and Xbox.com. It reflects the friends you add, achievements you earn, and games you play on Xbox.com in real time. You'll be able to compare your achievements with any other Xbox Live member just by logging in to My Xbox on Xbox.com. (Remember, achievements are new and can only be earned by playing Xbox 360 games.)

See your xbox360 stats on xbox.com friends, achievements, rep points, avatar, and you can even compare your rep or achievements with your friends. This can be used for xbox also but only to see friends.

If it says you are to young please read and do the following.

1st. Click and Sign in to this site
2nd. After Sign In go to "Account information"
3rd. Go to "Change your personal information"
4th. From there change your age. It has to be 18 or older so change it to 1987 or before that.

Nice! Thanks. :D I'd say this deserves to be stickied. :yes:

Yeah, it does!

I have done that today :)

Added some giudlines, of how to do it if you are uunder 18.