I was looking over at Scott Myers' BLOG, which always fascinates me. He's discussing outlines, and links to a post he wrote a while back: LINK HERE TO HOW PAUL SCHRADER OUTLINES, THEN RE-OUTLINES
Personally, I tend to write lots of notes about my idea, then write a short story of sorts, and then start the script. Sometimes, I don't need to refer to my notes, because the actual writing of the notes, then the story, has fixed things firmly in my mind, and I then feel free to write it in script form.
HOW ABOUT YOU??