I've started listening to quite a few podcasts lately, but The Polymorphic Podcast is different than most I subscribe to. While shows like DotNetRocks and The Microsoft Developer Show are technical in nature, the Polymorphic Podcast is technical. He gets into code samples and really discusses implementation details. It's a great podcast, and if you're a developer, you might want to check it out. The podcasts are short (15-30 minutes each) and I've listened to the whole archive over the past two days.
Thanks to Jason Salas for pointing this one out in his June 2nd episode of Digital Pontifications.