In 2001 or so, Rio brought out a stereo-component-shaped MP3 player based on the Empeg, designed to play audio from some machine elsewhere on your network. It was also sold under the SONIC|blue and Dell brand names. Its original price was a little high, but at today's eBay prices it's a reasonable and convenient way to play music. It's a fairly easily programmable little embedded box that just happens to run Linux and have an IR remote and the ability to drive a pair of loudpseakers.
It would be an exaggeration to say that there's a community of open-source coders improving on the original software, but a number of individuals have improved on various things before losing interest or being eaten by grues or whatever.
I've condensed Jeff Mock's scripts down into fewer (one to be called as a CGI, one to be run on the server to build an index, and an SSDP responder to be run from inetd). These scripts also allow the audio files to be located in arbitrary locations in the server's filesystem; I already had a collection of music I didn't want to rearrange, and building a tree of links seemed inelegant. In addition, they read the metadata from FLAC and Ogg Vorbis files.
The rioplay project on SourceForge hasn't seen much activity
since 2002. To keep track of my own changes to the source code, I've
set up a local Subversion repository.
browse it via
viewcvs. ViewCVS was too much trouble to maintain.
I also plan to place tarballs here occasionally.
The last sourceforge version is 0.29alpha1, and so I have been naming my versions 0.29alpha1-eldritch-blah.
The binary tarfile should be unpacked in the root of your rioplay filesystem (in my case, /tftboot/rio). Right now it contains the binary in bin/, and a stub of an HTML tree for the web-based player UI I may write someday.