If you mean you have a Windows Phone and can use your phone signal to connect to the Internet, there is an XBox 360 Application that let's you log on to Xbox Live, view and edit your profile, message other players, and more, if you have an account to log in to. It doesn't do games. But if you want to go play XBox games online, I believe you have to own a Wireless Router. Still, you can try. You could try to purchase an XBox Live Membership through the XBox itself when you get it, because I think you need Internet access to do that.
"What can this strange device be? When I touch it, it gives forth a sound
It's got wires that vibrate, and give music; what can this thing be that I've found?
See how it sings like a sad heart, and joyously screams out its pain
Sounds that build high like a mountain, and notes that fall gently like rain."