Burn ISO file on a USB Drive on Mac OSx

gistfile1.txt

Download the desired file
Open the Terminal (in /Applications/Utilities/ or query Terminal in Spotlight)
Convert the .iso file to .img using the convert option of hdiutil (e.g., hdiutil convert -format UDRW -o ~/path/to/target.img ~/path/to/ubuntu.iso)
Note: OS X tends to put the .dmg ending on the output file automatically. Remove the .dmg extension as necessary, mv ~/path/to/target.img{.dmg,}
Run diskutil list to get the current list of devices
Insert your flash media
Run diskutil list again and determine the device node assigned to your flash media (e.g. /dev/disk2)
Run diskutil unmountDisk /dev/diskN (replace N with the disk number from the last command; in the previous example, N would be 2)
Execute sudo dd if=/path/to/downloaded.img of=/dev/rdiskN bs=1m (replace /path/to/downloaded.img with the path where the image file is located; for example, ./ubuntu.img or ./ubuntu.dmg).
Using /dev/rdisk instead of /dev/disk may be faster.
If you see the error dd: Invalid number '1m', you are using GNU dd. Use the same command but replace bs=1m with bs=1M.
If you see the error dd: /dev/diskN: Resource busy, make sure the disk is not in use. Start the 'Disk Utility.app' and unmount (don't eject) the drive.
Run diskutil eject /dev/diskN and remove your flash media when the command completes
Restart your Mac and press Alt while the Mac is restarting to choose the USB stick


[Link : http://superuser.com/questions/63654/how-do-i-burn-an-iso-on-a-usb-drive-on-mac-os-x]