I finally found a fix for the unspeakable mouse acceleration problem I have with MacOS X. It's just a fact that Apple seems to have no idea how to do the mouse handling. Some people say it's the mouse acceleration curve that apple got wrong:

"As wonderful as Mac OS X is, it has a grave defect that can have an immediate adverse impact on the computer's usability: the way it translates mouse motion into pointer movement. For many users, moving the mouse feels unnatural because of the peculiar way that Mac OS X performs that translation. In industry parlance, the translation is called the "mouse acceleration curve." What is a mouse acceleration curve, and how is its implementation problematic under Mac OS X?"

It's a problem I can live with but I am not happy. With Panther and Tiger I had a solution called MacMiceCommand. But with Leopard this solution stopped working and until I found this:

"This is a GUI version of Richard Bentley's MouseFix. (i)MouseFix is a very simple program that will allow you to regain control of the mouse acceleration in Mac OS X. Both this web page and the program copies large parts from MouseFix because he says: "feel free to take the code and wrap a nice interface round it. Be nice and make it free for everyone to use though :-))""

Source 1: mouse acceleration explained
Source 2: http://www.lavacat.com/iMouseFix/