ABTO VNC server SDK provides you with toolkit to integrate VNC support into your applications (including .NET ones). VNC server together with the most popular viewers, including VNC viewer for .NET, allows stable connection with the remote computer, which hosts the server, and control of its operation. It can be used as an ActiveX component. VNC server can be accessed both directly and through repeater so it will work even behind NAT. The solution works on all Windows systems including x64 platform and is especially helpful in cases when you need to have unique IP in local network.
VNC Server SDK is shareware, you can free download and try it for free during trial period. After that you may buy it for $350 or should delete it.