Game Editor is open source and free to use, unless you want to sell your games. It's cross platform with options to export your games to Windows, Pocket PC, Linux, and
GP2X. I'm personally exploring the program to make my own game, ideally for the A320, but there's no option to export to it. I know lots of people here have made conversions for the A320, would it be possible to add in a A320 export function for Game Editor?
http://game-editor.com/Download