How to create ISO from Application Bundle I have Mac OS X Mountain Lion as Application Bundle file. Burning the application to a disk is just like a data disk compilation on Nero.

How do I convert this application bundle into ISO image so that I can burn it on a disk and boot it from there?
Right-click your "Install OS X Mountain Lion.app" file and select "Show Package Contents".
Open Contents/SharedSupport and then you will find InstallESD.dmg.

Copy this file to your Desktop. This is the file that you need to burn OS X to a DVD. You need a Dual Layer DVD to burn OS X/or just use a USB flash drive.

It isn't an ISO, but you can convert to a 'cdr' from Disk Utility. A 'cdr' file is the same as an 'iso' AFAIK, and you can rename the extension so that it is an ISO.