Apr 13, '10 07:30:00AM • Contributed by: swiney
First, download and install the open source KeyRemap4MacBook System Preferences panel. Once it's installed, go into System Preferences » Keyboard, and unmap all the special keys by checking 'Use all F1,F2, etc. keys as standard function keys.'
Switch over to the KeyRemap4MacBook panel, and remap all the special keys there, except for the one you want to change (in this case, the Exposé key). Expand the 'Remap F1...F16' section, then click on 'F5, F6 to Functional,' then each of the single key entries for 'F1 to Brightness Down,' 'F2 to Brightness Up,' etc.
Now you're back to where you've started, except you're allowing the F3 key to fall through to the system. You can go to the Exposé and Spaces panel and make sure F3 isn't mapped to anything in the Exposé pane, and is mapped to Activate Spaces.
