I had this exact problem. I have an employer-provided Dell Inspiron 9300 on which I was running FreeBSD 6.1. I installed suse 10.2 and it was absolutely insane. I didn't even need to actually slide my finger at all. Simply pressing it as if I were being fingerprinted was still barely keeping it in control.
What seemed to make it behave was to go into YaST, Hardware, Mouse Model, change Mouse 1 to an ALPS, deactivate Mouse 2. (I almost never bother with an external mouse.)
After that, just going into the KDE Control Center, Peripherals, Mouse section, I was able to tune it to my liking.