Share 'Book videos'

Hi. Has anyone created a book promo video for your website? Did it help your book sales? What format did you post? Quicktime??? Flash? And has anyone viewed any author book videos? Is it worth the time? I'm considering creating a video for my cartoon novel series, Cattle Capers (tm), but I'll have to draw the animation, which'll take some time (shortened up quite a bit by Flash). Is it worth it...