ndesk-dbus is a C# implementation of D-Bus. It's often referred
to as dbus-sharp, or "managed D-Bus" to avoid confusion with
existing bindings (which wrap libdbus).

D-Bus is an inter-process communication framework that lets
applications interface with the system event bus as well as
allowing them to talk to one another in a peer-to-peer
configuration.

Homepage:
http://www.ndesk.org/DBusSharp
