This 1987 documentary directed by Ken Viola features interviews with ten comic book artists. Kirby is the third of them, with a one minute introduction by Harlan Ellison followed by four minutes of Kirby talking, with a mix of Kirby artwork and video of Kirby speaking on the screen.
It's a fun but far too brief interview, very interesting especially for those of us who didn't get a chance to meet him. He talks about his motivations in coming up with the new and different, things that hadn't been done in comics before, to generate sales, and the biblical inspirations behind Galactus and the Silver Surfer. As he said, he was "a guy that lives with a lot of questions", and while he didn't come up with any answers to the big ones, he explored them in comics better than anyone.
Well worth checking out if you can as probably the most easily available video of Kirby, as well as such odd things as Ditko doing a voice-over about his beliefs over some Mr. A artwork.