Well, of a sort. I went out and bought a wireless LAN ADSL router and a wireless card, so I now have Internet access at home from my own PC. I'm already running XP SP2 RC2, so firewalling is covered (and I'm free of Norton Internet Security, yay).
I'll admit to being sorely tempted by a wireless adapter for my Xbox (which is in yet another room) but I could only find an 802.11b one - maybe I'll order a g version from somewhere else.
Anyway I'm now patching Office (2000 SR-1a - ouch) and getting files off the other PC. Which is a story in itself - the network setup wizard in XP Home SP1 is, er, a bit broken (yes, dammit, I want to call the workgroup something other than MSHOME, thank you so very much) and NIS is getting in the way somewhere still, I think. I can see the other PC and mine in Network (My Network Places, for those who don't habitually delete My from every profile they create) but from their computer - nothing at all.
The subtext is that I want to download Whidbey beta 1 but don't want to actually write CDs for it - and anyway the other CD writer is a touch incompatible.