Someone probably already posted this, but here goes:
http://www.comingsoon.net/news/movienews.php?id=20219
I'm watching GoF and I just noticed that the trolley on the Hogwarts Express carries Fizzing Whizbees, but they aren't sherbet balls, they're lollypops.

Doesn't seem like a change that serves any purpose. But I can see why there's no Pigwidgeon, he was a time-eater. (But Scabbers was a Death Eater, so I wouldn't mind having Pig in the movie.

)