Actually a whole bunch of them are, at www.groktalk.net, but mine in particular is at
My favourite part happens after the camera is off and we go to credits.
You can stream these, download them to watch at your leisure, or bring them down in the background with BITS using a tool like DrizzleCast. Full instructions are at the main URL. We've set each talk up as a blog entry so that you can comment and ask questions: you'll lower my workload if you comment there rather than here.