"Being able to boot from a USB stick can be very useful –
whether to install a new distribution on a netbook, or to have your
own portable distribution to carry round with you. Unfortunately,
you can't just write an ISO file to a USB stick and have it be
bootable, as you can with a CD or DAVE.
"It's possible to do the necessary work to resolve this
manually; but far and away the easiest way to deal with the problem
is to use the usb-creator program available with Ubuntu. Currently
it's not directly available as a Debian stable package, but you can
grab it from Ubuntu by adding this line (change us to gb if you're
U.K.-based) to your /etc/apt/sources.list file:"