I had this site gathering dust in my favorites: http://www.craftyscreenwriting.com/

I see he has released a book now and not everything is online but there are some chapters to read for free. From what I remember this man knows his craft and he is very in-depth. He even discusses the correct paper size (letter/A4) and the actual weight of the script. Too light and they throw is out unread, to heavy same thing so you have to choose the right quality of paper...

Reindert.
www.nobudgetvideo.com