I couldn't even get a minute into the movie before I felt like I had to jump out on to the internets to verify some of the material they were throwing out: "Horus [the Egyptian Sun God] had 12 disciples, was resurrected, ... was born on December 25th ... and that is why Christmas is celebrated on December 25th." This contradicted what I had thought previously; that Christmas was celebrated on December 25th because the Romans had made it that day to attract followers. Searching the internets for q=horus christmas returns little useful results. Searches for q=horus disciples actually turns up a lot of hits disputing that claim. Wikipedia's page on Horus makes no reference to Horus having 12 disciples or any kind of birthday.
Next up was this bit about "ages," or "eras", a period of 2150 years corresponding the movement of the Earth to the signs of the Zodiac. The movie says that the Moses ushered in the age of Ares, Jesus ushered in the age of Pisces, and the next age will be the age of Aquarius. Whistling a certain tune I headed out to Google again. q=jesus zodiac pisces returns 220,000 hits, but I wouldn't exactly call the top hits reputable; it's mostly people hawking astrological bible books. Some of the quotes on these pages look like a classified ad from the Weekly World News: "The Great Pyramid's 'missing capstone' has puzzled Egyptologists for centuries..." (But for $24.99 + shipping we'll explain everything!) q=moses zodiac returns similar pages. q=era 2150 returns a hit to the science fiction book "2150 AD".
OK. So the movie is a little flakey on the facts and references. In fact, here's a Google search about the movie that does return some reasonable hits: q=zeitgeigst movie bullshit -- 437,000 results!
As pure entertainment, Zeitgeist hits the mark. (A better title would have been "Illuminati: The Movie")... But seriously, if you're into this sort of stuff, I would recommend viewing Bill Moyer's Joseph Campbell and The Power of Myth, which is based on scholarly inquiry, not conspiracy theories. It's a little dry on the special effects, but at least you won't feel like you're being fleeced while you're watching it!
Update: Too funny. I just noticed the "statement" page for Zeitgeist says, "some information contained [in the movie] is not obtained by simple keyword searches on the Internet..." ...why? Is The Man keeping this information from us? It gets better: "It is my hope that people will not take what is said in the film as the truth." LOL. I've been pwned.