I think he means that he wants to run the router as a bridge; connect wirelessly to an already existing wifi network, and run a hardwired connection from it to the desktop nearby.
Some AP's and routers can do this, but typically they are higher end units. Your best bet is the wireless gaming adaptor that Dlink sells (cant recall model number, but I'll look it up later. It's around $100 (so you would have to spend a bit of money), but the good news is that it does support some pretty high end functions (including PXE if you want to get into that later), and if you plug it into a switch, you can use it as a wireless bridge.
-Luke