I am on a Mac G5 and need help beginning!
It looks like someone (http://forum.coppermine-gallery.net/index.php?topic=3205.0)has been able to set it up on a Mac. However, you need to first set up your Mac as a server that can run PHP and MySQL. Those are the minimum requirements (http://coppermine.sourceforge.net/manual.php#what) of using coppermine and we do not help with server setups.