I have been away for the weekend on a secluded island which means that I've had some time to fool araound with my GP2X.
I've been succesful reading input from the touchscreen*. It even worked at first attempt
If any are interested in it (have a GP2X F200), I've uploaded the code and binaries here.
It's not 100 % accurate since it isn't calibrated correct. I know some guys have manged to load the settings from the GP2X, so I'll have to look into that next.

*Thanks to joyrider, hangman etc. @ gp32x.com and their example c code.

@Paul
I've also taken a closer look at Eugenes code and worked a bit with SDL_Mixer. Blocks work fine regarding playing ogg-files via mixer. However when I wrote my own testprogram it worked fine on windows, but crashed on the GP2X. But when I compiled the program I got a warning that said something about static linking versus dynamic linking. Your batchfiles use static linking while Eugenes uses dynamic linking. I'm not an expert at this area, but it could maybe solve the problems with mixer if I used dynamic linking instead. However I couldn't compile it using dynamic linking. How do I use dynamic linking?