" The GCC IL frontend supports a wide range of legOS features including sensors and actuators. You can program the Lego robots with .NET and there no limitation on C#, because .NET assemblies are processed and source code isn't required. It is possible to program the Lego robots with all .NET languages (C#, C++, ...) and use the same set of functionality. "
Bernhard Rabe
Cool ! Check their weblog here. I found also a video but I can't find where I can download the RCX assembly.