I'm assuming you mean a story or idea, not a completed film. If you have a great idea for a movie, the first order of business is to produce a completed screenplay. Anybody can come up with a great idea. What will set you apart is your ability to communicate your idea in the form of a coherent script that tells your story in a clear, straightforward way, and has a definite beginning, a middle, and an end. Studios don't buy ideas, they buy finished scripts. As a writer myself, I can't tell you how many times a friend or acquaintance has said, "I've got a great idea for a movie! All you have to do is write the script!" (Which is like saying, "I've got a great idea for a computer game! All you have to do is write the program!") In terms of costs and materials, scriptwriting is the the least expensive part of the filmmaking process (all you need is a word-processor, a printer, and a stack of paper), however it is also the most important. All movies, big or small, good or bad, begin life as a humble typewritten script, usually about 110 pages, double-spaced. The script is the most important element of any movie, because, to paraphrase the great producer, Robert Evans, "if it doesn't work on the page, it won't work on the screen." If you're an inexperienced writer and you're not sure how to go about it, you can hire a professional ghostwriter to write the script for you, however that can be very expensive, so if you have reasonably good writing skills, the best thing to do is to write it yourself. Don't worry if you're not a great speller, that's what dictionaries are for. I'd be lost without mine! (I've been writing for 20 years, and I'm still the world's worst speller.) The screenplay is actually one of the simplest formats to write, much easier than narrative prose such as a novel or short story. It is the bare-bones framework of the movie you see in your head, and consists of nothing more than dialogue and basic descriptions of the action. (No camera angles, please.) If you've never written a screenplay before, don't worry. There's no mystery to it, and it's easy to learn how. First thing you should do is pick up a copy of a snappy little book called "Screenwriting," by Richard Walter. Mr. Walter is a veteran screenwriter who also teaches screenwriting at the prestigious UCLA film school, so he knows more about the business than anybody. You can get a copy of his book for about ten bucks at Amazon.com or your local Borders store. It's not the thickest book ever written on the subject, but it's by far the most informative and entertaining. Everything you need to know is in that book. The other invaluable resource you should become familiar with is a free website called SimplyScripts.com., where you'll be able to read and study--and in some cases, print out hard copies of--the actual screenplays of almost every movie you can think of. This is a great way to learn how the format works. It's not complicated, and after reading a few scripts, you'll know how to give your own script the look and feel of a professionally-written screenplay. Here's the link: http://www.simplyscripts.com/ After you've completed the final draft of your screenplay, you'll want to protect your intellectual property. You can send a copy to the US copyright office if you like, however most writers simply mail a sealed, registered copy to themselves. (The postmark on the unopened package proves when it was written.) If you plan on shopping your script around, you'll want to become a member of the Writers Guild of America (WGA), where you'll also want to register your script. The Writers Guild has a west branch in L.A. (http://www.wga.org/), and an east branch in New York (http://www.wgaeast.org/). Most studios will not consider unagented submissions, i.e., scripts that are not submitted through an agent. Agents typically take a 15% commission for selling your script, but that's money well-spent, since you'll be hard-pressed to sell your script without one, unless you happen to be best friends with a movie star (which most of us aren't). So it's a good idea to have an agent. And here again, the Writers Guild can help. The websites are filled with useful information on the subject, along with the names and addresses of agencies, and their submission guidelines. Get Richard Walter's book, and start reading scripts at Simplyscripts.com. Between the two, you'll learn everything you need to know about how to turn that great idea into the next blockbuster screenplay! Good luck!