Xbox Live allows users across the world to play games with each other over a broadband Internet network. The Xbox 360 is capable of connecting to Xbox Live via either a hard-wired Ethernet connection or wirelessly using a special wireless adaptor. Before you can connect to Xbox Live wirelessly, you'll need to have established wireless Internet in your home on a wireless network, which can be achieved using a wireless router connected to your broadband modem.
Attach the Xbox 360 wireless networking adaptor to the back of the console; this can be done by snapping the tiny plastic tabs on the adaptor into the plastic slots on the back of the console.
Plug the USB cable on the networking adaptor into the USB port on the back of the console and flip up the adaptor's antennae.
Insert the wireless network adaptor software disk into your console and install the software by following the on-screen instructions.
Go to the Settings tab on your Xbox 360 dashboard, then the Network Settings option. Once here, enter all of your router's information, including the name of your network and any WEP or WAP security keys associated with it.
Select the Test Network Connection option. This will test your connectivity. If it all goes well, you will pass the connection test and your Xbox 360 will connect to Xbox Live wirelessly every time you turn it on and start playing an Xbox Live-compatible game like "Halo 3" or "Madden NFL 2010." If it fails the connection, you will need to call Microsoft's tech support.