MediaTomb is a free, open source program running on Linux (and maybe other Unices), which serves various media files to UPnP clients. Maybe this is old news to you all, but I searched and found no references. Here is a "Howto" on using it:
http://en.gentoo-wiki.com/wiki/MediaTomb. It can serve various clients, including (I gather) PS3s but not yet Xboxes; however, my only experience is using it to serve my DirecTV satellite receivers, and thence my TV and Hi-Fi. It works, at least, to serve photo (jpg), audio (wav, mp3, flac, ...), and video files (mpg, avi, ...). I've been using it about a year, and the bugs have come and gone as MediaTomb and the client software have been revised. I use it to play music and videos I've downloaded from Usenet, since I don't have to pay anything for those. For instance, I found on Usenet around 3/4 of the old Alfred Hitchcock Hour/Presents TV episodes for my wife, and now she can play them any time she wants.
