My pal Karl Schroeder, a brilliant sf writer, gave an excellent interview to the Small World podcast. Karl is the best worldbuilder in the business, with novels like Ventus (a world of nanoaware semantically tagged devices gone mad), Permanence (an interstellar cult sets out to ensure that humans don't become nonsentient spacefarers who build space-ships like beavers build dams) and others (I've just finished reading and blurbing his incredible forthcoming novel Sun of Suns, which has wooden spaceships fighting zero-gravity kerosene-mine wars in a giant pressurized bag of fullerene that encompasses a lost civilization that has escaped the Singularity). Karl and I even wrote a book together, The Complete Idiot's Guide to Publishing Science Fiction.
Karl has blown my mind every time we've had a conversation, ever since I first met him in a writers' workshop at 16. He was the first person to tell me about fractals, chaos, Unix, gopher, and evolutionary psychology. His interview roams over numerous themes and subjects and provides some key insights into how he accomplishes his amazing, wildly imaginative world-building. He even talks about what it was like growing up as a Mennonite tech-geek.
(Thanks, Bazooka Joe!)