I bought a SMC Barricade wireless router and it works great. Nice in that it had compatibility with both PC's and the Mac advertised right on the box. With my setup, there are a coulple of PC's along with a mac laptop. It also has 3 of ethernet ports, so that you can hook up other computers to it.

It is configured through a web interface and the included instructions were quite straightforward. It was cheaper than a basestation, (prices on the net seem to vary from 130 to 170) and also has a parellel printer port and a modem port built into it, meaning that anything on the network can share that deveice.