Eject your CD/DVD drive. Place the MP3 CD in the drive's tray. Close the drive. Allow iTunes to "Autoplay" the disc or drag the disc's icon on the desktop to iTunes, if you're impatient. Then click play in iTunes.
In that case, your CD drive is probably broken. Of course, it could be that your Mac can't read the disk formatting (NTFS) the CD is using, but I don't think that's likely.
Have you been able to play a CD before, or have you just gotten this Mac?