I've downloaded the Windows 8 Evaluation Edition and got a zip. In this zip, I don't appear to have an ISO image? Have Microsoft stopped supplying it? I wanted to copy the ISO to a memory stick to install from.
Make sure you double check the hash to make sure it is the right file, I've seen in some cases mind you a computer viewing ISO's as zip or rar archives, as to why this is, it's usually a setting in whatever zip/rar program you use.