I am subscribed to far too many podcasts, but I am unwilling (for now) to reduce my current allotment in the science category. Here are the ones I have settled on:
The very best is The Guardian's Science Weekly. Alok Jha and his team are smart and entertaining, they have awesome accents, and they make no bones about talking about atheism. I miss the old opening electric guitar riff, but one can't have everything. If I could keep only one science podcast, this would be it.
Next in line is Scientific American's Science Talk. I like Steve Mirsky. His name is nowhere near as cool as "Alok Jha," but that particular bar is set very high: the only comparably cool names I know are Jagdish Bhagwati and Theodosius Dobzhansky.
Finally, there is the BBC World Service's no-nonsense Science in Action. It's no-nonsense.
Between these three podcasts, you should be able to get all the science news fit for public consumption, and then some.