How To: Install Portable Linux Ubuntu on a bootable USB Flash Drive from SUN VirtualBox

How To: Install Portable Linux Ubuntu on a bootable USB Flash Drive from SUN VirtualBox: " a fresh operating system on a bootable flash drive that will work the same way as from a real HDD (except the speed, of course). Thus, you should have a good bootable USB 2.0, with decent I/O data processing speeds, with at least 4GB (considering that the operating system itself weighs ~2GB, Karmic Koala)."