You can do 2 things:
1. Burn them with Nero or any burning program, into a DVD (or CD but I assume you are talking about DVDs) and watch the resulting disc on a DVD player or even in your computer.
2. Mount the image into a virtual drive unit, there are several "virtual drive" options, poweriso, daemon tools, alcohol 120. etc.
I think VLC can play isos, but I'm not sure, I don't use it that much.