PC/Chromebook:

http://animoto.com/

http://photopeach.com/

http://www.pixton.com/

http://www.storyboardthat.com/

iPad:

iMovie/Trailer $4.99

Directr -- free!

Splice --free!

Directions

Explain Everything (Voice over / no music) $2.99

http://www.haikudeck.com/

http://www.splashtop.com/

http://doceri.com/

http://www.educreations.com/

http://www.showme.com/

PC/Mac:

Imovie/ Trailer

http://www.techsmith.com/

http://www.apple.com/

http://www.telestream.net/

http://www.omnigroup.com/

http://deskscribbleapp.com/

http://flyingmeat.com/