One of the best places to hear interviews with top screenwriters is Jeff Goldsmith’s iTunes podcasts that are a part of the Creative Screenwriters Film Screen Series. Currently there are 100 interviews with various writers and directors and they are free.
Goldsmith is the senior editor of the magazine Creative Screenwriting and if you go to their website at www.creativescreenwriting.com you can link to it from there. Just look for “Free Podcast” and follow the promps. Great stuff.