Generally you should arrive about an hour prior to the movie; 2 hours or more if it's a good film. Why do you have to arrive so early? Because the movie screening passes do not guarantee admission. It is first come, first served until they reach capacity. The studio usually distributes a number of passes that would fill the theatre 3 to 5 times (to account for the no-shows). So if you are running late, you are probably not getting in. Yes, I have missed out on movies because I was not there early enough to get my ticket.
In most cases, you turn in your pass at the box office and then get in line. They usually open the theatre 30 minutes prior to the movie starting.
The press usually has a 'reserved' section of the theatre taped, roped off or otherwise assigned. Do not try to sit there as this is a great way to get kicked out.
Cell phones with cameras (and in some cases all cell phones) are generally not allowed. You won't know the rules until you get in line or about to eneter the theatre. Leave them, well hidden, in the car.
There are usually no previews before the movie begins.
Talking and cellphone use, like piracy, is very discouraged.
