Creative Commons is a service/Website that helps you generate copyright
licenses that grant/restrict exactly the rights you want. E.g., we use
this license for ScreenSite:

http://creativecommons.org/licenses/by-nc/1.0/

They also advocate for fair use of found footage. They sponsored a
contest recently (see below) for movies that express their objectives.
It's too late to enter now, but the first-place winner is a very cool
use of found footage. I recommend showing it to students (1) to show
what can be done with material like this and (2) to introduce them to
Creative Commons for possible use of its licenses on their own work.

The contest winners:

http://creativecommons.org/getcontent/features/movingimagecontest
"Building on the Past" is particularly cool.

-- CC contest --

WHAT: Create, or mash-up, a moving image that explains Creative Commons
mission, using your favorite moving image authoring tool, such as Flash,
iMovie, or Final Cut Pro. Entries can contain video, animated images,
text, and audio. We welcome and encourage the use of other people's
work, provided that you have permission or the work is Creative
Commons-licensed or public domain. The entry should be 2 minutes or
less. All entries must be licensed under a Creative Commons license of
your choosing by time of entry.

--
Jeremy Butler
Television: Critical Methods and Applications
http://www.TVCrit.com
ScreenSite
http://www.ScreenSite.org

----
Screen-L is sponsored by the Telecommunication & Film Dept., the
University of Alabama: http://www.tcf.ua.edu