For the XBOX. we did it one of two ways.. had the house set up wirelessly and the Wireless Router/ Modem next to where the X-Box was, so it was "Wired" to the router.. to go wireless you have to buy a special Wireless Gaming Adaptor, either from X-Box, or one that is X-Box compatible (go to Staples ask for Brian, he'll point you in the right direction) IF the 360 has a USB port, you might try the USB wirless adaptor ($39) I have it hooked up to my laptop and it works very well!
If you do go to Staples, tell Brian what you want to do, and he will tell you everything you need to buy (NOT commission sales at Staples, he won't sell you more then you need). Home networks are EASY!