A. Boot while holding down the mouse button. That should eject the CD during the startup phase. If that doesn't work, try booting into open firmware and ejecting the CD that way:
http://www.macosxhints.com/article.p...31210193237190
B. If you can't boot from the CD to install the operating system holding down the 'c' or 'option' key at boot, then you can try installing from another Mac via FireWire Target Disk Mode.