You don't really need a server edition of Windows, it'll still use the same ICS. You can use any of your PCs to act as an ICS host, but using XP should give better results. Unplug your crossover cable linking your XP Home and Pro machines together, then get some standard straight through cat5 cable and connect each PC to the ethernet switch. The switch holds your network together. (you could call it a hub, but a switch is the "better" version of the hub which is able to handle traffic better, but still provides the same function) You should get yourself an ADSL router as this is far better than software-based ICS. The router also connects to the switch, and will automatically give out IPs to your PCs.