Mounting an ISO image on Mac OSX does not require specific or additional software. Mac OSX, in fact, provides a tool (hdiutil) by which it is possible to manipulate disk images. For example, to mount an ISO image on Mac OSX, open your Terminal and enter the following command:

hdiutil mount /path/to/isoImage

/path/to/isoImage is the path to the ISO image to mount. After a few seconds, or better, after the checksum is completed, the mounted ISO image will appear on your Desktop and/or in Finder. For more information about hdiutil, enter the following command (in Terminal): man hdiutil.