I listen to some good podcasts about parenting by Dr. Meg Meeker, some religious ones like those of Dr. Michael Youssef, and some posted on Hope 103.2, which cover a range of topics. I think podcasts are great, and wish I could listen to more of them.
All the time. They're nice to listen to when I'm doing housework. It would be a long list, hmm... Some of the ABC ones like The Conversation with Richard Fidler, Bunga Bunga (comedy thing with Maynard and Tim Ferguson), a few about science and reason, like Skeptics with a K and Be Reasonable, The History Chicks (on women in history), Eff Yeah Film and Feminism... there are loads but that's all I can think of off the top of my head.