How to eject disc
The text below is from the Apple help section. Hope it works.
Ejecting a disc when all else fails
If you've tried all the usual methods of ejecting a CD or DVD disc from your computer's optical drive, there are some manual methods you can try.
First, quit all applications that are using files on the disc. Then try one of these alternate methods:
Choose Apple menu > Restart and hold the mouse key down until the disc ejects.
Put the computer to sleep (using the Energy Saver pane of System Preferences) and insert a large, straightened paper clip in the small emergency eject hole of the drive (the location varies, depending on the drive). Push firmly until the disc ejects.
Use Open Firmware to eject the disc if all other methods fail (this may not work on all computers). To use this method, you have to start up and briefly use the computer using Open Firmware, not the standard Mac OS X desktop. This is a simple procedure-try it if you're feeling adventurous.
To eject a disc using Open Firmware:
Restart the computer.
When you hear the startup sound, press and hold the Command-Option-O-F keys. (The Command key has an Apple on it.)
Release the keys when you see a white screen that says "Welcome to Open Firmware."
At the prompt, type:
eject cd
Press Return, then wait a few seconds. The disc drive should eject the disc, and "ok" appears on the screen when the action is complete.
Type:
mac-boot
Press Return.
Your computer starts up normally and you see the familiar Mac OS X desktop