Now that I've got two computers up and running here, I ordered a Linksys DSL Router/4-Port Switch. It was $70, plus free shipping, from EMS Computing (found 'em using Price Watch).
Now I'm going to have to rearrange my office, and start drilling holes in the walls and burying cable. Crap, for that matter, I actually need to buy some cable. =) One of the walls I'm going through is concrete, so that should be really fun to drill through. I'd prefer to install wall plates for the network connections, but all the outside walls are concrete in the basement, which is where both computers are now.