netboot.me

netboot.me is a service that allows you to boot nearly any operating system or utility on any computer with a wired internet connection - without having to know ahead of time what you'll want to boot. Once you can netboot.me, you never need to update your boot disk again!

UNetbootin

UNetbootin allows you to create bootable Live USB drives for a variety of Linux distributions from Windows or Linux, without requiring you to burn a CD. http://unetbootin.sourceforge.net