Xbox 360 USB Wireless Network Adapter

USB interface allowed Microsoft to get away from using an external
power supply such as those found in practically all wireless bridges.
This is what has allowed the adapter to match the Xbox 360 minimalist
design and connect on back of the console without any annoying cables.
This also frees up the built-in Ethernet port, and although Microsoft
has not yet revealed any intention to use the Xbox 360 as a home router
(for which two networking ports would be required), the possibility is
at least there and we are sure both Microsoft and Sony have paid
attention to that.

The second most important feature of this adapter is its dual band
capability. Although 802.11g remains the most popular Wi-Fi flavor,
because it offers the same bandwidth found in 802.11a while also being
backward compatible with 802.11b, the fact that 802.11g uses the same
band that microwave ovens and cordless phones utilize, results in some
interference depending on your home construction. If your router
supports it, using 802.11a, which works in the 5GHz range, is always a
good alternative.

More details about Xbox 360 USB Wireless Network Adapter