Eu uso MagicDisc .
Há também Clonedrive Virtual .
Além disso, veja estes links:
https://superuser.com/questions/3804/free-windows-iso-mounting-software
https://superuser.com/questions/14461/virtual-cd-dvd-softwares
https://superuser.com/questions/36499/windows-xp-is-there-a-small-free-way-to-use-and-mount-images-iso-files-withou