It's American Rhetoric, a site that gathers more than 5000 audio and/or video versions of
.... public speeches, sermons, legal proceedings, lectures, debates, interviews, other recorded media events, and a declaration or two.
This thing includes a selection of movie speeches. Want to hear the greatest pep-talk in literary history? This is the place for you!
Man, does Jason Streed ever deserve a giant cookie (with an equally-large glass of milk to go with it) for finding this one!
UPDATE: Lynn Sislo also linked this, via Jason.