HOWTO Convert an ISO file to a DMG file with no additional software. This article gives you two ways to convert an ISO file to a DMG file using nothing but your Mac & OS X.
This HOWTO article describes the simple process of setting the default application on your Mac that opens any file type. This is also called ‘file association’. You’ll mostly want to open pictures such as jpg, gif, etc with a certain program but you can apply this solution to almost any file type such as Microsoft Word documents, etc.