The XBox 360 comes with network capability built in, including a network plug socket. The wireless adapter lets you connect to XBox Live without a cable.

This wireless adapter is custom made for the XBox 360, and works on the USB port. The XBox 360 only has 2 USB ports, so this means if you plug the wireless connector into one, you only have 1 free for wired connectors or other devices.

This wireless adapter lets you connect to any existing wireless network in your home that uses either 5 GHz or 2.4 GHz Wireless A/B/G signals. Note that the wireless adapter merely sends signals to your existing wireless receiver. You have to already have a receiver running with a wireless network internet connection, to have this adapter "listen in" on.

Also note that the XBox 360 comes with a regular network port in it. That means if you already have a wireless network bridge for your other gaming systems, you can easily plug your XBox 360 into that bridge with a cable. The bridge would sit right next to the XBox 360 and transmit the XBox Live signal over to your receiver. This would give you the same connectivity without using up one of your USB ports.

You can get a bridge for similar or perhaps a bit more money - but because it's system independent, you could use it for your PS2 and your XBox as well.

In the end, if the only game system you have in your home is the XBox 360, it might be just as easy to buy this item here specifically made for that unit, to use the USB port. If you have other online game systems, look into one of the bridge options that will work with them all.

I want to note that you can of course play with a WIRED system if you want! Few people who write me have that luxury though - their XBox is far from any network port. Playing wireless means you can play literally anywhere in your house, regardless of where the incoming network port happens to be.

Buy XBox 360 Wireless Network Adapter from Amazon.com
Buy Wireless Ethernet Bridge from Amazon.com