Mouse Support
From Applepedia
MacOS X supports two-button and scrollwheel mice out of the box.
For more buttons, install the mouse mfrs own drivers (Microsoft, Logitech and Kensington have drivers, for example). If you don't like their drivers, or your mouse doesn't have drivers, use USB Overdrive.
The Logitech MX900 (Bluetooth) mouse doesn't have MacOS X drivers, although many people recommend GamePad Companion for binding buttons to features.

