I've only been a Mac user for a couple years now and I want to try Linux as well. I finally succeeded in downloading Knoppix and burning the image to a DVD+R.... now how do I boot from the DVD?? Mac Help's two good answers (change the boot volume in System Preferences or press Option while booting up) do not work. Neither does rebooting while holding the Command key.

I know exactly how to boot from a CD or DVD in Windows, but not in Tiger. Can anyone help me?