Prior to the movie coming out in a few months time the Focus Radio crew from Southampton have set up a site which has articles about the truths and myths within Dan Brown's book. Haven't had a chance to read all the pieces yet but look at Jesus and the Da Vinci Code if you want to explore further. At first glance it looks helpful.
The movie will be big, Tom Hanks is in it and people will talk so we may as well be informed.
I said a bit more about Dan Brown here. None of it particularly polite.