As many know I was interviewed for the film The God Who Wasn't There, which came out years ago and includes an extended version of my interview in the DVD extras. When I finally got to see the film, I privately circulated (eventually to journalists, academics, colleagues and others) a brief white paper on potential errors in it (only regarding the first third regarding ancient history, as that's my field). I then forgot about it. Several people recently have asked me about the film again, which reminded me I should just publish my brief. It is now available via my website as Critical Notes on the Movie The God Who Wasn't There (2005). Some of the points I make in that document I have since revised in subtle ways (as will be clear in my book On the Historicity of Jesus Christ), but it's adequate enough to stand un-edited from the original.
People have also asked me my opinion of the film. In general, the movie is as much about the supernatural God who isn't there (the Jesus everyone believes is going to come back from outer space and kill us) as the historical man who wasn't there, so it's not exactly a documentary about historicity (that subject only occupies something like a third of the film and is covered entertainingly but briefly). I find the film fun, funny, well-edited, and (for the most part) well-produced. It's definitely a feel good movie for atheists, and it definitely pisses off Christians to no end. I like it.
But it's not PBS edufare. GWWT suffers from the unavoidable problem of all entertaining documentaries: it oversimplifies things. But it's nowhere near as egregiously full of sh*t as Zeitgeist: The Movie, which has been thoroughly debunked as absolute garbage by several knowledgeable commentators (the best critiques are catalogued by Jim Lippard at the end of his own blog post on that awful doco). I wouldn't recommend Zeitgeist at all. But I only wouldn't recommend GWWT as a scholarly introduction to Jesus Myth theory. I still recommend it as awesome entertainment, played out with acceptable license. It takes liberties, but they aren't that excessive (as my white paper explains), and if you want authoritative discussion, you really ought to be reading a book instead.
[Though I grant you, there aren't any such books I'd recommend yet, beyond Doherty's The Jesus Puzzle, which is in its own ways flawed and incomplete--as you might glean from my critical review. Besides what you can read there, what I would say Doherty's book is lacking (and only because it's impossible for a single book to include everything) is coverage of a variety of essential supplementary topics, such as the fiction-myth analysis of the Gospels provided in Randel Helms' Gospel Fictions, which I also highly recommend (even though Helms doesn't argue Jesus didn't exist).]