Using Beta version 2.1 Build 1658.30 - I can not eject a CD from the drive using either the "Eject this disk" task or the MAC eject key. I have to shutdown the emulator to remove the CD.
I have found that I have to disconnect the CD in the status bar. OS X will believe (rightly so!) that the CD is in use until Parallels stops using the CD drive.
CD - Can not eject Even disconnecting it from the control panel does not release it to MAC OS, but assigning it to an image does.