I have just got into this and recommended listening to triple J, the best and most varied radio station in Australia.
http://www.abc.net.au/triplej/listen/podcast.htm
Especially Dr Karl's segment on Science:
It's roughly an hour devoted to the collective exploration of some of the great mysteries of life, such as "why does the water in the shower slow down just when it gets hot?". Most packages are between 40-50mins long and are without music.
http://www.abc.net.au/science/k2/podcast/drk_rss.xml
Hack, which is a current affairs show; but may be less relevant ot people outside of Australia:
http://www.abc.net.au/triplej/hack/podcast/podcast.xml
And Also John Safran who always has an interesting and humours look at religion, politics:
http://triplej.net.au/safran/podcast/safran.xml
Thaks for the other links - i'll have a looksee
