Linux Articles listed under "ubuntu usb installer"
Ubuntu 8.10 Live USB Creation The following tutorial covers the process of installing Ubuntu 8.10 to a USB flash drive, thumb drive or portable external hard drive using the built in USB Creator (produced by the Ubuntu team) to create a "USB Startup Disk". Installing with this method allows the use of the persistence feature (via a persistence loop file, FINALLY) to save and restore your changes on subsequent boots.
Create a Ubuntu 8.10 Persistent flash drive using the Live CD. This tutorial will enable a user to install Ubuntu 8.10 Intrepid Ibex to a USB flash drive while booted from the Live CD. In addition the persistence or casper persistent feature (via a separate partition) will be utilized to automatically save changes back to the thumb drive as you work, and then restore those saved changes upon subsequent boots.