Okay, this question gets asked alot. People asking about Xbox 360 and how to connect to Xbox Live. Here's the *Official* Xbox Live help section link: www.xbox.com/connecttolive
It's pretty simple, from there just choose your system either the Xbox or the 360 and it will tell you step by step on what you need and what to do.
Another thing, here's a link for people who need help on how to use the System Link to connect (2) Xbox Consoles together for multiplayer:
www.xbox.com/connecttoanotherconsole
There you go! all you need to know guys, so no more asking questions on that since it's solved! ha ha.