My personal suggestion is Virtual Clone Drive, a free program from Slysoft.
http://www.slysoft.com/en/virtual-clonedrive.htmlIt installs a "virtual dvd rom" that shows up under "My Computer" along with your other drives. Just double click on the .ISO file and it reads the ISO in such a way that it looks like a real CD/DVD in Windows. Then you treat it like you would any CD or DVD. As an added bonus, it hands lots of other ISO-style CD formats, like MDS, BIN, CCD etc...
This is different from programs like MagicISO, UltraISO etc... In that not only is it free, but you don't have to use the program's interface itself. You just use Windows Explorer to run and browse your ISO file like you would a regular CD or DVD...
cheers
