I've been listening to Science Friday via their podcast lately and I love it. It's a great science show published by the NPR.

"Each week, we focus on science topics that are in the news and try to bring an educated, balanced discussion to bear on the scientific issues at hand. Panels of expert guests join Science Friday's host, Ira Flatow, a veteran science journalist, to discuss science - and to take questions from listeners during the call-in portion of the program."

Science Friday is a little like the CBC's Quirks and Quarks but due to a labour dispute the CBC podcasts are on hold. In the meantime check out Science Friday's feed.