Creating an ISO image from a folder in Mac OSX

It is really simple in Mac OS, using the hdiutil command.  For example, you
have a folder named WINDOWS7_EN_DVD on your Desktop, and hope to create
a ISO image file for the folder so you can install it on a virtual machine, etc.

1. Open terminal window
2. Change the current folder to user's desktop, for example user is "Apple"
the type cd Users/Apple/Desktop
3. Type following command:
hdiutil makehybrid -o windows7.iso WINDOWS7_EN_DVD

A new ISO image "windows7" will be created on your desktop. You
may access to the ISO image as a CD/DVD device in Mac OS later.