Take a look at these book trailers to gather ideas for your creations:
Three trailers developed by Analine Johnson from her blog http://centeno.edublogs.org/

The Bearskinner retold by Laura Amy Schlitz and illustrated by Max Grafe

Savvy by Ingrid Law

Someone Named Eva by Joan M. Wolf ties in very well with studies of World War II and the Holocaust.

One of my favorite tools is Animoto. Here is a link to a student created trailer for The Vanishings by Jerry B. Jenkins and Tim LaHaye
Also, from the same blog, look at the trailer for Captain Underpants http://pettuselemmonson.blogspot.com/2009/09/animotocom_2932.html

H.I.V.E. - http://animoto.com/play/NNNcD9hZ2w2pHM0rZ027gA?autostart=true
Hooray for Diffendoor Day - http://animoto.com/play/FdVZ7CuQf001n6HyPhAvrA?autostart=true