Whoa, I got lucky
Ther’s a program called ‘MonoLingual’ for Mac OS X that deletes unused language files to save space. It also had the option of deleting keyboard layouts; I accidently deleted the US keyboard layout.
Luckily, my netbook was running a defunct version of Snow Leopard, so I booted Ubuntu on it, mounted the Snow Leopard install, and copied the keyboard layout to a flash drive. I then entered single user mode on my iBook, mounted the flash drive and copied it to /System/Library/Keyboard layouts/ and reboot. Now I can actually use it! For a while, I thought I bricked my new iBook :D
