I am selling my ibook and the only experience I have with formatting is windows. How do I do this with Tiger? I also installed the hack span, will the formatting take care of that as well?
Just insert the OS X cd that came with it, and follow the instructions.
It will be called clean install (or something like that - can't remember!)
And it will clear everything that's on it.
You can make sure the spanning hack goes away by first resetting your NVRAM. It's easy to do and you'll be able to test it for peace of mind before you go ahead and reinstall OS X.