Movie Magic Screenwriter is the one my son recommends as well. I still don't have the names of the books JtS uses, but when I do, I'll post them.

If you enjoy writing, and if screenplays are the kind of writing you want to be doing, don't let the odds keep you from doing it and enjoying it. If you're lucky (and good), something may come of it. But even if that doesn't happen, you'll still have something you can be proud of having created, and you will have had the satisfaction that comes with creating something you like and that you enjoyed creating. Plus, if what you write has Canadian content, you might be able to get some help from the government in getting it produced.

;-)