This is a last resort way of ejecting a stuck disk in a powerbook g4 aluminum. Before this you should try ejecting through disk utility, holding the mouse button at startup, try ejecting through iTunes, and try ejecting from open firmware (more info can be found on google). If all of these fail and your disk is still stuck try this:
Use a thin (stress thin) piece of cardboard or metal (I used tweezers and worked like a charm). If using tweezers make sure you squeeze them really tight so they're flat, then insert them all the way to the right of the drive as you hit eject. Push it in about 2 inches or so and move around a little until you feel as though you hit something and you hear some sort of click. You will know if the disk starts coming out and if so, take the tweezers out quickly. Then the disk should come out and you have not damaged anything.
If you mess up and do damage something internally, I am not liable (do this at your own risk).