One of the most popular searches for Windows 7 is how to mount an ISO image
in Windows, and now Microsoft has announced that it will be a native ability in Windows 8.
So how does this work in Windows 8? It’s quite simple – just “mount” the ISO file (you can select mount from the enhanced Explorer ribbon or double-click or right-click on the file), and a new drive letter appears, indicating that the contents are now readily accessible. Underneath the covers, Windows seamlessly creates a “virtual” CDROM or DVD drive for you on-the-fly so you can access your data.
Accessing data in ISO and VHD files [MSDN]
.