1) Download Ubuntu
2) Convert .iso the hdiutil convert -format UDRW -o ~/Desktop/ubuntu-11.10-desktop-amd64.img ~/Desktop/ubuntu-11.10-desktop-amd64.iso

3) Find the mount point of the USB via diskutil list
4) Format USB via diskutil unmountDisk /dev/disk[dnumber]
5) Put files onto the USB:

sudo dd if=~/Desktop/ubuntu-11.10-desktop-amd64.img.dmg of=/dev/rdisk[dnumber] bs=1m





TIP: REPLACE [] WITH STANDARD HYPERTEXT PROTOCOL.
TIP: REPLACE WHATEVER IS BETWEEN THE [] WITH YOUR INFORMATION.



Hope that helps!