MouseImp PRO is a successor of MouseImp that became popular all over the world. Many users’ wishes were considered in this new version of MouseImp, and many improvements have been implemented, making it even faster and more reliable.
With this extension, you can customize smooth scrolling behavior. The extension is worth to use, if you are frustrated at: Step size for scrolling by the cursor keys is so short. A built-in smooth scrolling is somewhat less sensitive and laggy.
Scroll Reverser is a free app for Mac OS X Snow Leopard and Leopard that reverses the direction of scrolling. With reverse scrolling, the page content moves in the same direction that you move your fingers, just like on iOS devices and OS X Lion.
Smoothwheel is an addon for Firefox, Thunderbird and SeaMonkey, which scrolls the page smoothly when scrolling the mouse wheel (or keyboard arrows if enabled). It works on all platforms supported by these applications.