Okay, if you want some pure, fried gold on the nitty gritty of screenwriting, you need to go to this link here - Scott Frank, in the Ask a Pro section of the Artful Writer forums, is answering questions, explaining how he works, and generally kicking ass and taking names. Yes, Scott Frank. Little Man Tate, Get Shorty, Out of Sight, Minority Report, The Lookout, and many more. You'll need to register in the forum to see the thread, but it's free, quick, and easy.
It's brilliant stuff, especially his thoughts on the sequence-based approach to writing scripts: "This gives me a headache. But if it works for you, go for it. I wonder, though, if Steve Zallian organizes his scripts this way. Or Tony Gilroy. Or Charlie Kaufman. Or Paul Attanasio. Or Paul Thomas Anderson. Or the Coens. Yes, now I that I think about it, Slumdog Millionaire could have benefitted from being a little better sequenced."
Go read. Now.