I ported the latest version of the Chipmunk physics library ( chipmunk-physics - Project Hosting on Google Code ) to PSP.
This port also includes the cpMouse module by Tommy Thorsen.
You can download the package here: http://gefa.altervista.org/chipmunk/....1_for_PSP.zip
(it contains the source code too)
Into the package there's a little demo written by me, already compilated and working both on fat and slim. It uses the oldschool library by sakya for graphic and input.