Copy CD to an ISO Image
dd if=/dev/cdrom of=/tmp/cdimage.iso
Adapt the command to the appropriate source drive in the if section and the destination directory in the of section to your needs. Please note that the /tmp directory is only a temporary storage and will be deleted when you reboot. It is recommended to move the ISO into another directory or initially set the appropriate destination directory in the of section.
To mount the created ISO image read the article "Mounting images as user".