I've been encouraging my students to make book trailers. My class are currently doing some as a follow-up to their Literature Circles and as a sweetener I've suggested we could enter any that are completed on time to the Inkys Creative Reading on Insideadog. The only headache was all the copyright issues. There are web sites with some creative commons free-use stuff on them, but try telling that to the boy who just wants a picture of a green Chinese dragon to go on his book trailer for Dragonkeeper!
However, there is, I have discovered, a "fair use" thing for education purposes and I am told that as long as you acknowledge, it should be okay.
Meanwhile, some of my book club members have been having a go. One of them is Kristen Huang, a young lady who simply loved Wolfborn. She wants to enter her trailer and I have put it up on Teachertube, but right now the thing is appearing without sound and I know the sound is copyright-free, because the artists on that web site did give their permission for free use of their music.
The images may be another matter, but she has acknowledged the web site and I'd like to say here that there is no intention to infringe copyright and it was done just so that we can enter the competition (prize: an e-reader, not money).