Help me set up a media server for my computer network on one of two old Windows boxes. I've recently gotten hold of two four-year-old desktop machines from my company. They have been wiped and have a clean Windows XP install on them.

My wife and I are generally an OSX household, but I'd like to use these machines to set up some sort of a media server: I have tons of movies and music, and would prefer to store them on a box in a closet and free up the space on my iMac.

Is there a way to do this? Can I install something like Ubuntu on one of these machines and connect via iTunes, or something like that? Or would it be better to leave them as operational Windows machines and do this all through iTunes?

If there's something obvious I'm missing about this question, let me know. I am not a super-skilled programmer/terminal user, but I can follow directions and used to be in AV club, so I have a knack for cobbling together solutions.