Neferchoirwen - Here's the link:
The Last Unicorn Movie. Can't wait 'til they post a message board! (Ack! Did I just say that?!)
Not that I'd ever go THERE!
As for the 5th O&FK book:
The Book of Merlin, it's been awhile since I read it, but it's kind of a "flashback" book, with references to WW II in it. The details are kind of fuzzy, since it's been years since I read it, but I don't think it's necessary to run out and get it, and I notice it has never been included in later editions of White's book.