imager is a disk imaging program that is designed to run under cygwin on Windows. This program will generate an ISO from a CD or DVD that is perfect for use with a program like Daemon-Tools or Microsoft's own Virtual CD-ROM Control Panel. This was originally written for my Dad who has some software on DVD that he uses alot and doesn't want to have to constantly wait for the DVD drive to spin up.

This will run on UNIX (might need some modifications) but you should really just use dd if=/dev/cdrom of=image.iso on a real UNIX.