I'm not an expert on VoIP (that's Voice over IP) technology, but I do know an interesting way of distributing software when I see it. 4S newcom GmbH has developed a new software based IP PBX (that's telephone switch to you, put simply). Normally, this wouldn't be something we discuss on TUAW, but they are distributing this software PBX on an iPod Shuffle (from the looks of it, it is the old style Shuffle). The press release says that even on the 512meg version (which will soon cease to be produced) there is room enough for the software and 4 hours of music.
The system also includes a Mac mini, which gets booted off the iPod Shuffle, after which you can install the software on the Mac mini.
2,999.00 Euros is how much you'll need to get this system when it ships on November 6th.