If you've been trying to swap the control and capslock keys on a new Powerbook and all the old tips aren't working, give this a try...
Edit the following file: /System -> Library -> Extensions -> AppleUSBTopCase.kext -> Contents -> PlugIns -> AppleUSBTCKeyboard.kext -> Contents -> Info.plist
Add these lines:
<key>Swap control and capslock</key>
<integer>1</integer>
to each of the entries in the IOKitPersonalities section. Save your changes, then do touch /System/Libraries/Extensions directory, reboot, and you're done! This hint is similar to John Fieber's instructions.
Mac OS X Hints
http://hints.macworld.com/article.php?story=20050210002402105