Windows 7: Emulate CD/DVD Media on your machine.
I have been happy with Virtual CloneDrive for quite a while now. Today I stumbled upon a .NRG image that it won't mount as a drive and I wanted to have that image in a more popular format.
After some hunting, I decided to go for Daemon Tools, as they offer a free-for-personal-no-comercial license for their lite version of the product.