So recently i have been attempting to configure my xbox 360 to run some what wirelessly, of course you still need the ethernet cable between the xbox and your iMac/MacBook/what ever mac you're using, but it saves the hassle from having a 20M ethernet cable running through your house, and all of this is done WITHOUT the $100 microsoft attachment. The setup in OS X lion is amazingly more simple then in previous OS X's, and it seems that "trying too hard" was actually the problem with not being able to get it to work. Instructions: PART 1 [Mac] Firstly on your mac go into System Preference > Network then click on Ethernet, and under Configure IPv4: select Using DHCP. Now return with Show All, select Sharing in your preferences then select Internet Sharing (do not tick yet), in the drop down menu of Share your connection from: select Wi-Fi then under To computers using: tick Ethernet. You may now tick the Internet Sharing box NOTE: Ensure internet sharing is green PART 2 [Xbox 360] Starting from Xbox dashboard, My Xbox > System Settings > Network Settings > Wired Network > Configure Network NOTE: At this stage there should be a little tick in the top right hand corner at the Wired Network stage Now that you're in basic setting, go into both IP Setting & DNS Setting and change these both to Automatic. Now carry on to test your connect, you will get a warning saying: "You can connect to Xbox LIVE, but your current network configuration may limit your online experience.." From experience i havn't been able to notice any difference but i guess according to the message that could be different for you.