I talked about this earlier.
The mono tools for Visual Studio is a commercial product that easily enables you to test and port your Windows applications to mono.
As I told before this is really a great idea. Because I think Visual Studio is the best IDE and Linux is the best server OS (in my opinion, it’s more efficient and more robust than Windows Server). So, I think it’s the perfect gateway between this two very different (but very close since Mono appeared) environments to achieve greatness.
And if you don’t want to buy it, well, you don’t have to. Mono is free and you can very easily test your Windows programs on it. You just have to install mono, copy your exe (plus its required DLLs) to the Linux host and type something like “mono SampleProgram.exe”.