Nope, just a pci wireless card for the second PC. There are 3 'flavors' of 802.11 - a,b & g. Just get a router and a pci wireless card that supports 802.11g...
Tim, This is how it's physically connected: cable > cable modem > router > pc (either wired or wireless) Having stated that, you're going to need a wireless-g router (the kind with 2 antennas is preferable) and a pci wireless-g card for the other PC. The router and the wireless-g card...