This will show you how to turn a downloaded iso file into a bootable usb drive using mac osx
there are two methods.
the first is the better way:

• go to unetbootin.sourceforge.net
• download it and follow the instructions

you will now be done.

the following method is the old way to do it (before unetbootin was available for macs)

• open terminal
• plug in your usb drive
• in ternimal type:

• mount

you will get an output that has the name of your usb drive volume in it, it will be something like /dev/disk2s1

• in terminal type:

• diskutil unmount /dev/disk2s1 

  [what you found from the mount command]

• in terminal type:

• dd if=/path/to/file.iso of=/dev/disk2s1 bs=1m

  [what you found from the mount command]

it will then copy the content of the iso file to the usb drive.