I remember watching Scream 3 with the commentary on and remember a few facts that were said by Wes & the producers.
1: The security guard that comes into the studio when Sarah is hiding between the ghostface costumes, is the same guy who has been in Scream 1 & 2 playing various characters in the background.
2: Neve Campbell was wearing a wig in the movie the entire time since she was doing another movie at the same time and had long hair in that movie.
3: The scene when Gale first meets Dewey again in the studio, was 3 days after they came home from there "real life" honeymoon and were really tanned in the entire movie which made wes laugh.
4: Wes Craven had Neve Campbell for 20 days only for the movie since she was in the middle of starring in another, which explains why she hardly appeared in the third movie.
5: The Mansion that was used in the end of the movie was the same building that was used in Halloween H20 and many other horror movies.
6: The scene where Sidney opens the book case, and enters the "secret" room the room she enters is actully country Cox's house (at least one of them i heard Wes say).
if i remember anymore i'l edit it and bump the topic.