For the new wireless keyboard.
Install this software to take advantage of your 2009 aluminum Apple Wireless Keyboard's special features.
Mac OS X 10.5.8 is required before installing this update.
For detailed information on this update, please visit this website
Note: For Mac OS X 10.6 users, the 2009 Aluminum Wireless Keyboard support is included in the Mac OS X 10.6.2 update.