Saw the movie myself, my personal opinion on the matter: The producers took a great story right out of the pages of history and turned it into ****. Elephants are not that big, I don't recall ever reading about Rhino's being mounted as cavalry, Xerxes certainly wasn't nine feet tall, there were two kings in Sparta not just one, I highly doubt there were that many Africans in a PERSIAN army, Sparta certinaly wasn't a grand city with massive public works, and the Spartans did wear body armor, which was very effective for its day.
Basically it's like this, if you don't care that much about history and can look past all the glaring inaccuracies it's a great movie, if you're like me and (going out on a limb here) Phoenix you probably won't like the movie.