I posted a presentation on programming VI with .NET using the VI Toolkit (for Windows) to slideshare. If you're looking to develop a .NET application for VI and not looking to use PowerShell, this presentation shows you how to simplify C#, VB, etc. programming using an assembly distributed with the VI Toolkit (for Windows).
Check it out at
http://www.slideshare.net/vmwarecarter/using-vi-toolkit-for-windows-from-net