Qyoto makes it possible to develop Qt and KDE applications using C#, or any other .NET language. Qyoto uses SMOKE, and offers access to almost all Qt and KDE classes.
The current version of Qyoto is maintained on Gitorious.
An older (not actively maintained) version of Qyoto is part of the kdebindings module in the KDE SVN repository.
$ git clone git://anongit.kde.org:qyoto
You can also browse the source online.
Pre-built binary packages are available in the following distributions: