I've mentioned this once before but wanted to point toward it again because in my recent workshop I gave out the wrong link for it: the site is Meet the Author (www.meettheauthor.com) and it contains almost 900 videos of authors pitching their books to camera.
The man who runs the site makes short videos (for a fee) of authors talking about their books. The resulting videos appear on this site as well as on the authors' sites, some bookstore sites, etc.
It's a brilliant source of examples of how to pitch well...and how NOT to pitch. If you spend a bit of time roaming around randomly you'll see everything from suave confidence to sheer terror on display. Great fun to watch--and learn from!