How can i change my mac password without knowing the original?

I own a ibook g4 but i dont know the password I need a way to get the password without doing any permanent damage to my computer or having to pay any thing.|||You don't have to have the original OS X dvd, but you do need to have an OS X dvd (borrow one from a friend). When you boot to the OS install disc, choose an language, and then go to the Utilities menu, where you'll find the password utility.