ZeroConf SharedRecords?

ZeroConf, known by many names (Rendezvous, Bonjour, mdns), is a simple service discovery protocol.

References

•  http://en.wikipedia.org/wiki/Zeroconf - excellent Wikipedia article
•  http://jmdns.sourceforge.net/ - pure java implementation
•  http://avahi.org/ - Avahi is implementation that is popular on linux
•  http://developer.apple.com/networking/bonjour/index.html - Apple's developer page