You use and like AMC, and want to contribute to the project? Here are some ideas...
Promote AMC among your friends or colleagues, on a website and in forums... A large users community will help AMC to develop.
Help other users
Correct and extend AMC
Report problems and bugs to make AMC more robust. You can use your linux distribution bug tracking system, or the one from the project site, or contact the author.
If you are using a linux distribution on which AMC is not officially packaged, perhaps you can fill in this gap?
You can also help to translate the graphical interface into a new language. Contact the author for advice and coordination.