poooh for macally for lacking this button...
but a quick search on macally.com/techsupport says:
Q. I have the new PowerMac G4 that does not have an eject button on the front panel. How do I use the Key to open my CD tray?
For the eject button for Mac OS 9 please follow these steps.
Option 1
1. Please go to your apple pull down menu, control panels, and keyboard.
2. Select function keys.
3. Select one of your hot function keys.
4. A window will appear.
5. Select Desktop from the pull down menu.
6. Open your hard drive, Applications (Mac OS 9), Apple Extras, Eject
extras folder, and choose the Eject application.
7. Close the window and test the F key that you have assigned.
Option 2
1. Download the OpenTray folder file
2. Copy the extension into yor Extensions Folder
3. Restart your computer
4. Press command+Esc, the CD tray will open or close
For Mac OS X, the F12 is the eject key.