Instructions
Turn on the Xbox 360.
Open the dashboard by pressing the Guide button and pushing "Y."
Go to the dashboard's "My Xbox."
Scroll right to find and select "System Settings."
Open "Network Settings." The console scans for wireless Internet connections and displays a results list. If you do not see your wireless Internet connection, make sure your console is within reasonable range of the access point. Most routers have a range of approximately 50 feet. View your router's specifications to determine the wireless range.
Select the wireless connection from the list. An on-screen keyboard pops up.
Type the wireless connection's password. You must know the password in order to connect. Refer to your router's manual to help determine your password if necessary.
Press "Start." The console connects to the Internet.