(commercial) Edge is a true multi-platform game engine for mobile devices. The Edge platform, written from scratch in C++, enables you to produce high quality, commercial games.
This is a complete development environment for GP2X development as a complete
preconfigured package (needed as many people are having problems setting up the
toolchain, IDE, etc from the Wiki).
Simple Dev Studio
Simple Dev Studio is a very small IDE for GP2X SDK for those who want to develop a small application.