Apple Computer's implementation of the ZeroConf [L1 ] network configuration and service discovery protocol, formerly known as Rendezvous.
A Tcl package for Bonjour is available at http://github.com/dongola7/tcl_bonjour/ .
lordmundi: This is a great package. I think many people may be missing it since they are searching for things like "DNS-SD" or DNS Service Discovery, or mDNS. To help out these keyword based google searches, this package will let you do DNS service discovery browsing, publishing, and resolving in tcl. If you aren't familiar with DNS-SD, you can learn more about it here:
http://en.wikipedia.org/wiki/Zero_configuration_networking