On the other hand, there's the Mono project...
Oh.... good! I didn't know about it. How exactly this is working? Does a piece of code in c# has to be changed a lot to compiled under linux? Or c# works like Java (that any standard-compliant code can run on any os that has the Java runtime environment).
Yeah, it's quite similar to Java. The program is compiled to a bytecode, which is platform independent. The .NET exe's and dll's only contain this bytecode. Before the progrsam is launched on a given platform, it's first compiled to the machine's native code and then execuded (this is different from Java, because Java is interpreted, hence slower). So, in theory, you can use the exe compiled under Windows and run it on a different platform. And as far as I know the Mono runtime does this on Linux and other free OSes. Of course, for this to work, the program must not use platform dependent calls, such as calling native DLL functions or COM objects. Also, the .NET framework library needs to be ported to the given platform (or at least some parts of it, because it's really HUGE and some parts are patented by Microsoft).
And I just love the C# language
Does it really has so many good features for a windows-programmer?
It has nothing to do with Windows, it's a fully featured programming language. It builds on C++, but many things have been changed to allow for safer programming and better convenience.
Ok, the downside is it's closely tied to the .NET platform.
EDIT2: Just because I am really curious : Is wme interprenter (and NOT the tools) uses A LOT of windows-specific-code (except the DirectX ofcourse)?
Not really. Of course, the renderer and the texture and sound managers rely on DirectX, but they are strictly divided from the rest of the engine. Also the main loop is totally windows dependent. And there are some small things used everywhere, such as Windows functions for working with rectangles, but those could be changed easily.
Of course, the tools are totally non-portable
EDIT3: If you think that I am asking to many questions about wme, please say so
Not a prob, ask away