From the developer: The USB Overdrive is a driver for Mac OS 9.x or later that handles any USB mouse, trackball, joystick and gamepad from any manufacturer and lets you configure them either globally or on a per-application basis. It reads all kinds of wheels, buttons, switches and controls and supports scrolling, keyboard emulation, launching and all the usual stuff like clicking, control-clicking and so forth. The USB Overdrive can easily handle several USB devices at once.
Version 1.4 enables mouse wheel scrolling in Classic applications under Mac OS X 10.2 and later. New features under Mac OS 9 include a 'Use Global Settings' command, support for the Logitech MX500 and MX700 8-button mice, support for the Microsoft Sidewinder Strategic Commander, support for GyroPoint devices, and more.