Pascal, thanks to the Free Pascal compiler, can be used to develop GP2X software, GP2X games can be built games by using its ARM-Linux cross compiler. The best way to get started is to download the official releases of the ARM-Linux cross compiler, this cross compiler generates programs useable by the GP2X out of the box. GP2X development can be done using SDL. In this case the JEDI-SDL toolkit is used. Direct hardware access is no problem either. The Pascal Game Development website has usefull resources how to get started with JEDI-SDL and you can share your experiences with other SDL and GP2X coders on the forums.
Free Pascal offers great possibilities to use assembler code in your games and is therefore also a good tool for coders interrested in assembler programming on the GP2X.