Can I use my existing wireless network to connect to Xbox Live?
Wireless LANs are not officially supported for Xbox. Depending on the distances involved, the construction of your home, sources of interference, you may not get good performance from a wireless solution. The setup is also not for the faint of heart. If you know what an SSID is, then you might be ok, but if you don't, you should probably stay away from using wireless for your Xbox. To put it another way, it's possible to get wireless to work for Xbox Live, but our support staff can't help you do it.
Have a look at
xbox connection the answer may be there somewhere!