My first screenwriting book was called, "The Complete Guide to Standard Script Formats: The Screenplay" written by Judith H. Haag and Hillis R. Cole. I bought it while writing my first screenplay, an adaptation of Mary Shelley's Frankenstein. It's a bad script. But then, so are most scripts churned out by 17 year olds. The one thing it's not, however, is poorly formatted. In fact, it's formatted pretty nicely. I still have it, the original pages, printed out character by character from my old Brother word processor. I still have the Cole/Haag book, too.
With software progams taking care of so many of the intricacies of the form -- pagination, spacing, margin width -- the old book isn't as vital as it used to be. But I'd argue even a little vital is still vital. If you don't own the book, Amazon.com presently has 75 used copies starting at $2.80.
If you want to be a screenwriter, it's simply a reference book you must have on your shelf.
