ASP.NET and C# can be run on the Apache webserver. See Mod_Mono: http://www.mono-project.com/Mod_mono
.NET can be run on Linux, Solaris, Mac OS X, Windows, and Unix.
See Project-Mono: http://www.mono-project.com/Main_Page
One of the disadvantages with .NET, ASP.NET, and C# is the cost of the Integrated Development Environment (IDE), but the IDE (Visual Studio) is well worth your investment. You can develop .NET applications through text editors and alternative IDEs, but much efficiency / productivity is lost.
- Adam Kahtava [http://adam.kahtava.com]