I always thought that there was a fairly large amount of information available on the battle, but mostly from the Mexican side- officer’s diaries and battle reports, etc…
Here’s a good link:
http://www.tsha.utexas.edu/handbook/online/articles/view/AA/qea2.html
Take heart in the fact that the script was written by the King of Research, John Sayles. It’s being rewritten, of course, but with luck they won’t abandon whatever foundation Sayles has created.
You know, that much-maligned car wreck of a movie 1941, actually had several historic incidents re-worked into it:
The Japanese I-class subs bombarding the coast (they did this in Oregon, British Columbia and California–but not to an amusement park);
The “Battle of Los Angeles,” where reports of unidentified aircraft led to jumpy AA gunners opening up;
Dan Ackroyd’s excellent checklist on the loading and firing of the Ordnance, 40mm, Anti-Aircraft, Mk. I. (These were sited here at Fort Rodd Hill in such a fashion that they could be used as AA guns or anti-shipping role).
The Bounty , the 1974 release with Gibson and Hopkins, was mostly accurate–assuming that Richard Hough got things right in the book it was based on (Captain Bligh and Mr. Christian), which was well researched.
Assuming that the same is true of Rudolph Grey’s book Nightmare of Ecstasy, Ed Wood (1994) was pretty accurate too.
Oops! Change 1974 to 1984.
If you want a bizarre experience, do some research on Billy the Kid and the Lincoln County War. Then watch the movie Young Guns.
It’s weird. They got a lot of tiny details right, enough that I know that someone did some serious research. (I can even tell you one of the books they probably read: Violence in Lincoln County, 1869-1881 by William Aloysius Keleher)
Then they completely changed most of the major elements of the story. So you have a movie where the main plot is complete fiction, but many minor elements are accurate.
It’s funny; sometimes a director (or maybe the art director) will make a fetish out of accuracy, and then for the sake of a stupid plot point, they’ll have some ridiculous distortion or anachronism. In Robin Hood: Prince of Thieves, for example, they went to the trouble of finding short-legged, shaggy cows to be in the background to help establish a 12th-century countryside… then they threw in gunpowder (over a hundred years early for Europe) and a telescope (four hundred years early). (Incidentally, the telescope they showed should have presented its image upside down.) Both these ridiculous elements were completely unnecessary to the story.
Heheheheh.
U-571, BAD WWII movie about submarines.
Das Boot, GOOD WWII movie about submarines.
That’s all. 
Say what you may about Titanic (and bashing this movie is apparantly a rule here on the SDMB), but, plot aside, you will likely never see a more faithful and accurate recreation of the Titanic and it’s sinking for as long as you live.
One I just saw yesterday that will win no awards for historical accuracy: Yankee Doodle Dandy. Great film, a must-see if you haven’t already. Trivia: it was directed by Michael Curtiz and it was released the same year (1941) as another, slightly more famous movie of his: Casablanca. He won B. Director (for Casablanca), Casablanca won B. Picture, and Cagney won B. Actor for Yankee Doodle Dandy. Sometimes you just have one of those years where everything seems to fall into place. 
Enemy at the Gates: Foolish me for thinking that the Russian army would speak with Russian accents.
I think movies that base their stories on historical events and people do have an obligation to strive for accuracy. They are messing around with real people, and when you deal with real people you do have an obligation to their characters- even if they have been dead for years or centuries.
If you want to make up a story, just make up a bloody story. Why bother dragging in real events just to rearrange them to your liking?
From Hell featured all the most far-fetched and ludicrous Jack the Ripper conspiracy theories and the world’s earliest lobotomy to boot.
Elizabeth. Help me out here. Was Marie of Guise really stabbed to death in bed by Elizabeth’s lover who pretended to seduce her?
The sick thing about that-it’s true. Not that they were MUCH better off, but things certainly grew worse.
Oh well.
I still liked the movie-and I would never have become so interested in the Romanovs otherwise, and met so many friends online in the Romanov/Royalty communities. Nor would I probably have chosen Russian history as my major.
Also, speaking of little details, Anastasia DID indeed have a lot of them correct. For example:
The drawing she gives her grandmother was an exact replica of a watercolor the real Anastasia gave to her father.
Alexei’s ghost limps when he comes out of the tapestry-the real Alexei had hemophilia and often walked with a limp.
When her sisters surround her, they do look a lot like the real Grand Duchesses-even down to Tatiana’s bob.
The real Anastasia was born at Peterhof-though not at the Palace, but at the summer dacha.
Alexandra’s ghost is wearing MAUVE, as is the figure in the music box. Mauve was the favorite color of the real Alexandra.
Silly details, yes, but interesting, at least. And fun to look for.
Their personalities-the real Anastasia was certainly a little brat who would constantly get in trouble-and would sometimes only behave if ordered to by her father.
Yeah, sugaree, Elizabeth got to me, too. I think I must have been the only person in the theatre thinking, “Enough of this love story crap! Let’s get to the politics!”
As a historian, I have sort of a love/hate relationship with movies based on historical events. If I don’t think too much about, I can really get into movies like Braveheart, but if I let down my guard, the little (and big!) inaccuracies will start to niggle at me. I’m not saying they have to get everything exactly right, but when they invent characters out of whole cloth or change things around completely it really gets to me. It’s like when a filmmaker adapts a novel and completely changes the ending. I refused to see Disney’s Hunchback of Notre Dame because I knew there was no bloody way they were going to be remotely faithful to Hugo’s text.
Amistad bugged me. The real story behind the ship and the court case is fascinating and fairly different from the movie. Plus, as in many Hollywood movies that are ostensibly about civil rights/slavery/Navajo code talkers/etc, it’s really about more white guys becoming enlightened than anything else.
Pocohontas was so very wretched on so many levels that Disney really should issue on apology to history teachers for generations to come.
Maybe I’m misinterpreting what you wrote, but isounds like you are saying that the British Royal navy captured the first Enigma Machine.
I believe this is wrong. Wasn’t it the Poles who captured the first one (and did a lot of the initial work on decoding Enigma ciphers before Hitler and Stalin carved up Poland). If I wasn’t so lazy I’d find a cite, but I’ve read it in several sources and thought it was common knowledge.
Well, on the bright side, they stopped screwing with classics after that.
At least Disney never got ahold of Hugo’s other famous novel Shudders.
“At least Disney never got ahold of Hugo’s other famous novel Shudders.”
Oh come on!!, Wouldn’t it be fun to see Les Mes redone in cartoon form with animals??..i have to go take a bath in boiling water now 
Not common enough for Hollywood, obviously. I’ve heard the same thing as you, and although the Polish work was of huge importance (I certainly wouldn’t want to underplay that) the naval-variant Enigma was much harder to crack and required the capture of Kreigsmarine Enigmas in 1941 and 1942 ( cite ).
So instead, they turned to pulp in 1999. Tarzan is, I’d think, one of the few cases where the story actually improved in its translation to the film.
For one, animation was really the only way to capture Tarzan’s abilities on film with any accuracy, so it was really the first film to elegantly show Tarzan swinging from branches rather than just grabbing a vine and holding on for dear life.
But in the books, Burroughs was rather racist. The Porters weren’t the first humans Tarzan ever met; they were the first white humans. Jane wasn’t even the only woman in that party; she was the only white woman. Tarzan and the apes aside, everyone else in these novels was a stereotype. The more Tarzan books you read, the more annoyed you get by how casually these racial stereotypes are sprinkled throughout.
And while Clayton was the typical “white hunter villain” from the novels, I wish they’d named him anything else. Although he’s not revealed as the villain until later in the movie, there really was no point in giving him Tarzan’s family name (or, for that matter, making Terkoz the rival ape into “Terk”, the wise-cracking sidekick).
In terms of special effects, but otherwise, not; at least according to this:
http://www.titanicsociety.com/readables/main/articles_04-11-1998_cameron_apologizes.asp
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