From the comments on the article
Best Free CD / DVD Emulation Software, Total Mounter has been mentioned.
It is a virtual CD/DVD burner and a freeware alternative to some commercial programs. I've tried Total Mounter and somehow experienced system crashes on two separate PCs, one running on XP and the other Vista. I've written to the developer and understand from them that they will carry out more detailed tests, and solve these problems as soon as possible on my case.
At the meantime, I'd appreciate your feedback here about your experience in using the program before I consider to include this freeware in the article.