Converting image files on OS X

I just learned today from Zackary (http://blog.zloether.com/2009/07/convert-cdr-to-iso-in-os-x.html) that I can convert one disk image type to another in OS X.  Here is an example of the command

hdiutil makehybrid -iso -joliet -o [filename].iso [filename].img

The example converts .img file to .iso 

Very usuful!