Unetbootin is an application which allows you to create bootable flash memory devices such as SD cards or USB memory.
In addition to the manual selection of image files there is a large selection of OS distributions to choose from which will be downloaded from an online source.
A full list of featured distros along with the installation packages (also including the Windows app) can be obtained from
Unetbootin is also included in the Ubuntu repository so you can install it using:
apt-get install unetbootin