Iso files are much like archive files. They can have multiple files and folders inside of them. I find they can be a clean way of housing many files. Of course, once you have them, you need a way to mount them in windows ( linux and osx have built-in ways of mounting them)

So the very first ( and free) way to mount iso’s
winxpvirtual

This one takes a bit of work to setup:

1. Copy VCdRom.sys to your %systemroot%\system32\drivers folder.
2. Execute VCdControlTool.exe
3. Click “Driver control”
4. If the “Install Driver” button is available, click it. Navigate to the %systemroot%\system32\drivers folder, select VCdRom.sys, and click Open.
5. Click “Start”
6. Click OK
7. Click “Add Drive” to add a drive to the drive list. Ensure that the drive added is not a local drive. If it is, continue to click “Add Drive” until an unused drive letter is available.
8. Select an unused drive letter from the drive list and click “Mount”.
9. Navigate to the image file, select it, and click “OK”. UNC naming conventions should not be used, however mapped network drives should be OK.

The second is Called Clone Drive(free)
http://www.slysoft.com/en/download.html

The third is called MagicISO (free)
http://www.magiciso.com/tutorials/miso-magicdisc-overview.htm

And the last is one called WinCDEmu
http://sourceforge.net/projects/wincdemu/

There you have it, 4 ways to mount iso’s in windows. The majority of the programs listed here have walkthroughs on their respective sites.