This right here is your best bet, though the drive you mention is listed on that page as being in the PowerBook G3 (Pismo), not the iBook. Are you sure you got the right drive model? I've got an iBook myself that I've used the SR-8176 firmware on with success.
Remember, once the drive is region free, your friend will still need to use
Region X to reset the Apple DVD Player, as it will want to limit the region changes to five, even though the drive itself will have no such limit.
And as for installing it in OS X, there ain't any hacks I know of that can do that. All the ones listed on that page work only in OS9. But your friend doesn't have to install it as such; just put a minimal install, plus the firmware hack, on a CD, boot from it, then run the firmware hack. It will probably work.