If I can find detailed instructions, I'll do it. (Gulp, does that mean I nead to download or burn a linux CD again? That took me 8 days to configure last time, and I can't say it was a lot of fun.)?
Pentium II or III of around 500 MHZ [this is the most important component for getting a good points/kWh ratio].
128MB RAM. [256 to run the 600 point WUs efficiently]
Just about any Video card or onboard video chip.
Network card [or onboard NIC]
Power supply compatible with m/b
2 to 3 GIG HD
Win98SE [W2k if you dislike rebooting and having to save big WU directories at various points along the way so the whole thing never gets wipped out by a crash/reboot]
m/b compatible with above [generally one starts with a m/b one already has - kinda like Armies and Wars ;-)]
Home network with internet sharing so the additional computer can just have the NIC jacked in to get to the 'net.