Eh, it's just typical extremist Christians who are taking things way too far. I'm a Catholic, and yes, the books are meant to be a critique of the Catholic Church prior to the Reformation, when there were huge amounts of power abuse. However, I'm a big fan of the books, and I plan to see the movie.
The Catholic League's assertion that the movie is bait for the books is giving the filmmakers way too much credit. I highly doubt there's some grand conspiracy to spread Atheism through the use of movies, and even Nicole Kidman has said she would not be involved with the movie if she felt it was as controversial as Bill Donohue would say. But she is, she's proud to say that, and she's a mainstream Catholic.
Bill Donohue and the Catholic League do not speak for all of us, many of us would not be sad to see him drop off a cliff somewhere.