I have a Fedora 10 installation and use it actively. While I do most of my development on Windows XP I try to make all my programs portable accross as many platforms as possible. I can compile all of my projects under Linux, though due to certain undeveloped parts of code I don't have full functionality for certain things (like mouse). I am intending to improve the Linux portion of my code to include the missing functionality, hopefully in near future. I do intend to develop for MAC also, and it should not be a major problem to port.

All my game projects are based on OpenGL and OpenAL. My own engine as well as my networking code, and all other components I use are portable.