I added a sample .NET Windows Forms client project to source control. The project is an example of using the CM System Web Services API from a .NET perspective. The project was created in Visual Studio 2008 in C# and borrowed some code from the Loader C# sample client that ships with CM System.
The source needs a few tweaks to make it more usable, namely the Preview logic expects Rhythmyx to be running locally, but it should be a good starter for anyone interested in using Web Services via .NET.
-nate