How to quickly launch preferences for volume or screen brightness in Mac OS X

To instantly launch the preferences controls for audio or screen/display settings, simply hold down the Option key (between Control and the Apple command key, i.e. the Alt key) then press one of the keyboard shortcuts for either volume or brightness control. Newer Apple keyboards have re-mapped these keys, so exactly which keys you press depend on the age of your keyboard; the controls are usually marked on the keyboard.

Some more keyboard volume tips:

• To move the volume up or down in tiny steps, hold down Shift and Option when you tap the volume keys, this will move the volume in quarter steps. (Possibly this is Leopard 10.5 only, I can't remember it in Tiger 10.4).
  
• To silence the volume feedback "blips" noises which trigger at each step, hold down the shift key when adjusting the volume. The noises can also be turned off completely on the Preferences Sound controls window, uncheck "Play sound effects"