I always love it when people who have made it to the top give back and share a little bit of their experiences and how they got there.
John August, screenwriter of Big Fish, Go, Corpse Bride and Charlie and the Chocolate Factory to name a few. He hosts a blog (http://johnaugust.com) that hosts how-to's and provides examples of script outlines, pitches and shooting scripts. Apparently, he also writes as a featured columnist on IMDB occasionally as well in the 'Ask A Filmmaker' section.
Definitely check out the rest of his site, it's chock full of useful posts. What I wanted to feature though, was something that took a little digging to find. He apparently also has screenwriting videos that he calls 'Scriptcast' that range in topics from re-writing dialogue, to improving scene openings, scene description and writing better action. So I wanted to toss up just one of these incredible videos for you to check out.