The Ubuntu site has excellent documentation, but I kept running into an error when it came time to mount the image onto the USB so that I could have a LiveUSB ready to go. This slimy error read, “The disk you inserted was not readable by this computer.” It would happen everytime I tried to execute sudo dd if=/path/to/downloaded.img of=/dev/rdiskN bs=1m.
I had quite the search trying to find a simple solution for this. I attempted to mount the image multiple times and nothing seemed to with the USB full partition set as MS-DOS. The fix was quite simple and a small program that does all of the steps for you once you’ve downloaded the OS from the Ubuntu site. Just go to http://penguintosh.com/ for the readme or download the program directly at http://www.mediafire.com/?rctco14mzjayaa9. The program comes with detailed instructions and handles the entire process for you. Let me know if this is of any help!