The lack of wireless USB networking is a bit of a pity. If it was possible, then I could keep my Amigas in a separate room, away from the PCs. But it looks like I'll have to sit them on the same desk and use a USB-Ethernet dongle to get me connected to my network router.
You should get an Edimax BR-6204Wg and run it in wireless bridge mode. Then you can connect up to four computers to it by ethernet and have them connected to your wireless AP with WPA/WPA2.