Source: http://feeds.feedburner.com/~r/lifehacker/full/~3/376620606/unetbootin-creates-usb+bootable-linux-the-easy-way
Windows and Linux only: Free bootable image creator UNetbootin automates the downloading, imaging, and installing of Linux distributions onto USB thumb drives, creating a persistent, boot-anywhere desktop. We've previously featured rather involved guides to putting Linux on a flash drive, but UNetbootin does it all for you, from downloading the right ISO to setting up a USB stick as a bootable Linux drive. It can also convert almost any bootable ISO, so if you've got an old, smaller thumb drive not seeing much use these days, you can use UNetbootin to install a partition editor, a file-recovering live CD, or the Windows password-cracking Ophcrack. UNetbootin is a free download for Windows XP and higher and Linux systems.