Boot and run Linux from a USB flash memory stick | USB Pen Drive Linux
http://www.pendrivelinux.com/
UNetbootin (というツール)
http://unetbootin.github.io/
LinuxLive USB Creator: Powerful yet easy-to-use
http://www.linuxliveusb.com/
(紹介記事)
LinuxのLive USBを作成する「Linux Live USB Creator」http://www.moongift.jp/2009/07/linux_live_usb_creator/