How to create a Windows 7 installation USB from OS X? I'm trying to create a Windows 7 installation USB (for use on a PC) from OS X.

I've tried following these instructions from a similar question on superuser:


Insert the USB flash drive and run the command diskutil list to find out the disk name, we'll use /dev/disk1 as an example
Now unmount the disk using diskutil unmountDisk /dev/disk1
dd if=/path/to/Win7.iso of=/dev/disk1 bs=8192


But the instructions don't work. When I insert the created USB drive into my PC and try to boot from it, I get this message:


  Reboot and Select proper Boot device or Insert Boot Media in selected Boot device and press a key


What am I missing?
Turns out OS X Lion ships with Boot Camp 4.0, the coolest feature of which appears to be the ability to create install USBs.