Mono.Zeroconf is a cross platform Zero Configuration Networking library for
Mono and .NET. It provides a unified API for performing the most common 
zeroconf operations on a variety of platforms and subsystems: all the 
operating systems supported by Mono and both the Avahi and 
Bonjour/mDNSResponder transports.

By using Mono.ZeroConf developers can use a single API that will work 
regardless of the underlying implementation that a particular operating 
system uses.

Developers can publish services that will be exposed to other computers on 
the network and also query the local machines on the network for services 
that could have been exposed.

More information about Mono.Zeroconf can be found on its project page 
on the Mono Wiki:

   http://mono-project.com/Mono.Zeroconf

General information about Zero Configuration Networking: 

   http://www.zeroconf.org/