Oh yeah XP is fine - I've had it, in various situations, doing a simple machine - machine crossover connection, hub connections and switch + router business and it's worked fine every time (note this is XP Pro. I've heard bad stories about XP Home).
Next academic year should be fun.
1 x NTL 1mbit cable.
1 x old P200 running
IPCop to connect the cable modem to.
2 x hubs
8 x whatever machines housemates + me are connecting
Going to work first time?
I don't
think so!