After a little googling I found this:
What are other good examples?
I think Story by Robert McKee is good. It may not go into some of the technical details you may want, but is a great book on how to tell a story.
I think 'Screenplay - the Foundations of Screenwriting' by Syd Field is considered to be "The Bible" in this area. Great book.
There is great support for script writers and film makers available from the BBC, including free advice and film showcasing.
They also have a published guide to writing, including sample screenplays by both professional and amateur writers, with in-depth reviews on each.
The first book you should buy is The Screenwriter's Bible by David Trottier. This is the complete guide to formatting in hard copy. While you may rely on software to format, knowing your formatting is equally as important.
Syd Fields' - The Foundation of Screenwriting is also a great place to start. This offers the basic steps in regard to screenwriting.
But truthfully, if you want to learn how to write in a screenplay format, with all the elements of the three act structure, inciting incident and big event, the mid-point turn and the third act turn, character arc, subtext, foreshadowing, and everything else that comes with a great script, then you need to write and read.
I spent a year at Trigger Street reading and reviewing screenplays for others. While it was a year of frustration - you tell someone their script is weak and they tend to tell you to go fish - but the reward was coming away with a great deal of knowledge about what doesn't work.
Films are visual media, not dialog-driven media, unless you are Tarantino. Knowing how to direct the camera with the written word without ever giving a camera direction is a skill that can be learned.
The first important thing about screenwriting is this:
The field is very tough to break into. If you don't live in L.A. the chances of your work being found and produced are so infinitesimal that it can be discouraging. Get an L.A. post office box and a cell with an L.A. phone number and be prepared to go there at the drop of a hat.
But don't do that until you learn to write.
Second, you need to write about a dozen scripts before you get this down. With editing and polishing you may invest several years to learn the craft.
Finally, there are a great number of businesses that will take your money to "teach" you how to get in to the business. There are websites that profess they have producers come to them for new and exciting scripts. There are quite a lot of people who claim to be experts. Since the advent of the internet there is a whole cottage industry created to get you to fork over money.
Don't. Spend your time writing, and reading other's scripts at places like Trigger Street or wherever (I am not shilling for Triggerstreet, btw).
Plus, IMDB is your friend. When someone tells you they have the path, then look them up on IMDB. If they truly have produced films, you'll know. If they are full of beans, you very well could find that out too.
Most likely, you will not get any action there at Trigger Street or Zoetrope, but you will get a wealth of knowledge you cannot get by forking over 700 bucks for a three-day weekend with some guy who makes his living cashing your check and not actually working in the industry.
But the best advice is to move to L.A., get a job at a studio or with a prodco and meet people.
That, more than books, tutorials, lectures, and workshops that are all trying to sell you something wrapped up in the disguise that they have the secret to getting famous in Hollywood, is the best way to get into the business.
Keep in mind a fool and his money are soon parted. In this realm, that goes double.
William Goldman, author of The Princess Bride and the script for Butch Cassidy and the Sundance Kid, wrote Adventures in the Screen Trade and Which Lie Did I Tell, both of which are essentially memoirs that have insights into how he became a successful screenwriter. (They're also a lot of fun to read.)