Disk Utility. (Disc = CD or DVD)
Look in your Applications > Utilities folder
Try restarting the computer.
Try the drive in another computer. It may be coincidental but the drive may have failed.
Found Disc Utility
*Sigh* Disk Utility (there is a difference and if you use the wrong terms people will think you need something diferent).
What's the difference between a "disc" and a "disk?" - http://support.apple.com/kb/HT2300 - optical cf. magnetic.
Edit: You posted while I was typing this response.
Can you repair the drive (not permissions, the other thing)? If you can, do so, then eject the drive properly.