Move the filesystem to a USB drive/stick

This was actually my very first post on the raspberrypi.org forums.
It has been visited 279000+ times, so it has been useful to many people.

I was honored when the forum guys selected this post as "sticky", making it easy to find.


Recently, I updated the procedure to more reflect the changes in Raspbian.

Here is the link : https://www.raspberrypi.org/forums/viewtopic.php?f=29&t=44177

Enjoy!