Description of the PC-Link protocol (this is the network protocol used by the MC-i200 to share music across the network): http://www.siteswap.org/streamium/protocol.html.
streamiumd – a great pearl software by David Witt and Nathan Peterson
streamiumd is a streaming software that can be run on computer to offer mp3s for the MC-i200 to be played. It replaces the PC-Link Software (special version of MusicMatch Jukebox).
I put a copy of the code on https://github.com/pklaus/streamiumd.
Download the script: http://www.witt.tv/streamiumd/streamiumd and save it somewhere:
cd ~/Downloads
wget http://www.witt.tv/streamiumd/streamiumd
chmod +x streamiumd
chmod 700 streamiumd
sudo apt-get install libmp3-info-perl
Start the server, make it show up as Philipp's Server, and serve mp3s from ~/music/JohnnyCash: