Working with Images and USB
From GcatWiki
hdiutil convert -format Rdxx -o /Users/letaylor/Desktop/fedora\ 12/Fedora-12-ppc-disc1.img /Users/letaylor/Desktop/fedora\ 12/Fedora-12-ppc-disc1.iso
diskutil list
diskutil unmountDisk /dev/disk1
sudo dd if=/path/to/downloaded.img of=/dev/rdiskN bs=1m
diskutil eject/dev/diskN