After updating to Mac OS X 10.2 from 10.1.5, I decided to remove MouseZoom since the new mouse control panel seemed to accelerate my mice satisfactorily. Unfortunately, even though I deleted the MouseZoom.prefpane file from my hard disk, the MouseZoom icon still appeared in my System Preferences window, even after restarting.
Ben Hines, MouseZoom's developer pointed me in the right direction by suggesting that a cache file existed somewhere that might be causing the problem. I quickly found such a file does exists here:
/Users/username/Library/Caches/com.apple.preferencepanes.cacheI simply deleted the above file and then reopened the System Preferences window and voila, the MouseZoom icon was gone. Yay!
Mac OS X Hints
http://hints.macworld.com/article.php?story=20020827082503509