A couple. Start by holding down the spacebar when you boot. If that doesn't work, move on to the mouse button. If those don't cut it, you need to open up the system profiler program, and under disc burning, does it recognize that the drive is there?
And it has to be asked, but you're aware you need to HOLD the eject button, and merely pressing it will NOT be enough, correct? Sorry, but sometimes people don't know the basics of the basics. I once had a person unplug a computer I had set up for them, and then complain to me when it wouldn't work... Because they unplugged it. There's a reason all troubleshooting starts off with questions like "Is it plugged in?"
If the above doesn't work, or no drive is listed, you'll need to take it somewhere to get the drive replaced because it's dead. They should also be able to remove the drive from the system, then open it to get the disc out. I recently had to do that for an iMac. The good news is, your disc is almost certain to come out of this unscathed. The bad news, is that if your AppleCare plan has lapsed, this won't likely be cheap.
I have a macbook.
I have an audio cd in the drive but it will not eject.
I've tried rebooting and hitting 'eject' button after the chime
I've tried rebooting and hitting 'F12' after the reboot chime.
I've turned my computer off overnight and tried the above steps again.
iTunes does not recognize a disk is in the drive.
Finder does not recognize a disk is in the drive.