American Freethought "Question. Think. Decide."
Apologia "a friendly forum for both theists and non-theists to come together in search of some common understanding"
Are We Alone SETI
Astronomy Cast Astronomy Today
Books and Ideas Dr. Ginger Campbell, M.D.
Brain Science also by Dr. Ginger Campbell, M.D.
Chariots of Iron Atheiskeptihumanists™
For Good Reason James Randi Educational Foundation
Freethought Radio Freedom From Religion Foundation
Gresham College Audio public lectures since 1597...podcasts being a recent development
London School of Economics The LSE has plenty of seriously smart people lecturing on economics, politics, and the social sciences
NPR's On the Media exploring "how the media 'sausage' is made"
On Being formerly known as Speaking of Faith, with Krista Tippett
Point of Inquiry Center For Inquiry
PopTech Audio "world-changing people, projects and ideas"
QuackCast Dr. Mark Crislip, M.D.
Rationally Speaking New York City Skeptics
Reasonable Doubts "your skeptical guide to religion"
Reasonable Faith Just remember "You are not qualified to debate William Lane Craig"
Righteous Indignation from the U.K.
RSA Events: Audio the Royal Society for the encouragement of Arts, Manufactures, and Commerce
Skepticality Skeptic magazine
Skeptics with a K from the U.K.
Skeptoid Brian Dunning
TED Talks my only video feed (and no, I don't watch it during my commute)
The Skeptic Zone from Australia
The Skeptics' Guide 5X5 Five minutes with five skeptics (from the NESS)
The Skeptics' Guide to the Universe New England Skeptic Society
Token Skeptic from Australia
Unbelievable from the U.K.
Try one, you'll like it.
PS The language used in some of these podcasts may not be suitable for all listeners.
PPS Drivetime podcast listeners in Minnesota should be careful not to look like they are attempting to "compose, read, or send an electronic message, when the vehicle is in motion or a part of traffic," as that is a violation of 169.475 USE OF WIRELESS COMMUNICATIONS DEVICE.