Change which key allows you to zoom into the screen
How to Open the System Preferences in Mac OS X Leopard
An introduction to the Universal Access pane, enable VoiceOver, Zoom, Hearing, Keyboard and Mouse options
How to zoom into the screen in Leopard.
Change how the screen moves while you're zooming into it
Enable access for assistive devices
Make your screen flash when an alert appears
Make your mouse cursor larger in Mac OS X.
Enable sticky keys, allowing some users to use keyboard shortcuts and commands easier
Use the arrow keys on the keyboard to control the mouse
