If you're lucky enough to be running GNOME, there's a nice little utility that will handle all of the chores of mounting, unmounting and ejecting CDs for you. If you right-click on your GNOME panel, choose Panel -> Add to Panel -> Applet -> Utility -> Drive Mount, you should see a neat-o floppy drive icon in your panel. Now, right click it and choose Properties. In the Mount Point line, you should see that it probably defaults to the floppy drive. Change that to the mount point of your CD-ROM drive (probably either /dev/cdrom or /mnt/cdrom). Change the Icon to Cdrom, and click the "Use automount friend status text" and then click OK. There you go! Now, when you insert a CD, you can just click the drive mount icon and it will do it all for you. When you're done with the CD, click the icon again and it should unmount it.