The Creative Screenwriting Podcast talks with film and television writers such as David Hayter (Watchmen, X-men) Joel and Ethan Cohen (No Country for Old Men, The Big Lebowski) and the entire writing staff of The Office about the process of writing. The list of interviews is very impressive, and no doubt you'll be able to find an episode about a movie you've seen recently.
I just listened to the Watchmen episode last night and found David Hayter's explanation of the ending pretty reasonable. He also explains why he didn't use the "hacksaw" situation from the prison breakout scene from the comic book (he said it was too reminiscent of a similar situation from The Road Warrior, which I'm not sure is a good enough reason). He didn't quite explain all the Skinemax scenes though. Anyway, it's interesting to hear writers defend their decisions, and explain the writing process.
Inter-web Links :
The Creative Screenwriting Podcast on iTunes