Virtual Clone Drive

Virtual CloneDrive works and behaves just like a physical CD/DVD drive, however it exists only virtually. Image files generated with CloneDVD or CloneCD can be mounted onto a virtual drive from your hard-disk or from a network drive and used in the same manner as inserting them into a normal CD/DVD drive. 

Probably the best virtual drive software, Virtual CloneDrive allows you to enjoy the freedom of a virtual drive and is completely free.