Is there a such thing as a wireless network adapter that is NOT USB connected?

How about a PCI wireless adapter??

This does exist. It is called a wireless network bridge. Many salespeople don’t know it because it looks kinda similar to a router but I have one made by Netgear. It cost about $40 and works great with my USB 1.1 desktop. It looks like a router and plugs into your ethernet port. Your computer will think it’s attached directly to a wired network. They have them at most tech stores including Best Buy and Circuit City. Hope this helps!

You can use something like an Airport Express to do this – it looks like a power brick, has an Ethernet port, and is easily configurable to join a wireless network and bridge it to the Ethernet port.

I’m sure other manufacturers make something similar, but that’s the one I have experience with.