Startup Disk Creator

Startup Disk Creator (USB-creator) is an official tool to create Live USBs of Ubuntu from the Live CD or from an ISO image. The tool is included by default in all releases after Ubuntu 8.04, and can be installed on Ubuntu 8.04. A KDE frontend was released for Ubuntu 8.10, and is currently included by default in Kubuntu installations. 
The KDE and Ubuntu frontend go under the names "usb-creator-kde" and "usb-creator-gtk", respectively.
Future development.
The tool is available for Ubuntu (GNOME [From 11.04 up to 17.04 also their own called Unity]) or Kubuntu (KDE) and also for Windows starting in Ubuntu 10.10 "Maverick Meerkat" but accessible only by inserting the Live CD into a CD-ROM drive with Windows running.