I'd just noticed the other day that my MacBook was no longer mapping the caps-lock key to control. Since I, always one to jump on the latest fad, had just been playing with zsh, I thought it was involved. However, it turned out to be a little Snow Leopard Feature. The Keyboard preference pane "modifier keys" dialog now has a drop-down selection list for which keyboard, and you now have different settings for each keyboard. In other words for a laptop you can have different settings for the internal keyboard and an external keyboard (maybe even different for a usb vs. bluetooth external keyboard) Not only that but it would appear that the settings for the internal keyboard can be different depending on whether or not the external keyboard is attached.