You can...but it would be difficult...
You have to first rewrite the system coding that tells the thing what it is and what its input devices are...
tell it, it has buttons and how to check when they are pressed. tell it where the screen is and how to display things properly. then you would have to build a programing language into it so it could actually do something and then from there you would build apps for it



If I were going to do anything I would just mod sony's existing firmware to a point where it is like a pocket pc...

you could always just install pocket pc or windows but I don't believe there are umd reader drivers for windows...and even if there were there is no actual way of playing the game on the console...and from that point it is technically not even a psp anymore its just a pocket pc in a psp shell