Warren James interviews George R.R. Martin on the legendary Hour 25 SF radio show in December 2000, when A Storm of Swords had just come out in the US (at the time it had been out in the UK for four months). GRRM discusses the ins and outs of publishing, his approach to writing, and his days working in Hollywood. (And of course, how many books it would take him to finish the saga.) It's a fascinating interview with a guy who was a seasoned genre veteran but not quite a celebrity bestselling author. When I listened to it in 2001, it convinced me to break my longstanding embargo against epic fantasies and pick up Game of Thrones.
(Keep in mind that this is from an earlier, pre-podcast era of the Internet, so the only links available are streams. I'm kind of surprised that no one's turned Hour 25 into a podcast, since the show still runs intermittently on the Web, and there is an amazing wealth of material in the archives. And that's just from the early '00s.)