Your router and Xbox 360 are on completely opposite sides of your home, running a long, ugly wire along the floor is out of the question, and you don't feel like dropping $100 on an Xbox Wi-Fi adapter? If you've got a laptop with Wi-Fi, Instructables details how to use it as an Xbox 360 wireless adapter. In all its a really simple process involving sharing your laptop's wireless internet connection with your Xbox through an ethernet cable. It's not as good as a wired connection, but if you don't regularly rely on the connection, it's a good workaround. If you want a slightly more permanent solution, you can also build an Xbox Wi-Fi adapter on the cheap.Source- http://lifehacker.com/340158/use-your-laptop-as-a-free-xbox-wi+fi-adapter
This is an awesome way to get WiFi connection to the old Xbox 360. If this doesn't work for you though, and you're looking for a nice alternative, I've got just the thing for you. Check out this Xbox 360 Internet Connection Kit from Netgear, it acts the same way as a WiFi adapter, giving wireless internet connectivity for your Xbox 360, and it also works for your PS2, PS3, and PC gaming. Check this link out: http://bit.ly/bByST7, for more information about this wonderful product from Netgear.