Matt Bird at 2010-09-14 13:51:50:
Yes, totally, it's the one book every screenwriter should read. I actually just did a big 19-part post about Campbell and Jung, which I called "The Hero Project", over at my blog.
What I concluded was that, though Campbell himself preferred Jung, the journey he describes is very much a Freudian journey, in which the hero has to want to change, but there's another journey I call the Jungian journey in which the hero merely has to learn to accept himself.
Click on my name if you want to check it out. The Hero Project entries are listed first in the sidebar. I go specifically in Campbell and Jung in entries 1, 9, 10, and 13.