Scrollability is a control panel which allows you to scroll through documents in two fundamentally new ways. With Scrollability's gesture-driven scrolling, simply moving the mouse into the upper or lower edges of a window will scroll the window in the appropriate direction. With the grab scroll feature, you can invoke a small hand cursor to grab the contents of a window and drag them up and down, just like the hand tool in many graphics and page-layout programs.
Scrollability is a Control Panel for Mac OS 7-9 only. It works in the Classic environment under OS X, but not with OS X native applications. If you're interested in something similar to Scrollability that works with some OS X native applications, take a look at MaxiMice or, for Grab Scroll functionality, Smart Scroll X.