One of the terrific science learning resources available on-air and online is Science Friday. Every week, host Ira Flatow talks with scientists about a broad range of topics. These programs air on PBS stations and are available as podcasts. Great listening!
But wait, there's more. The web site includes blogs, supporting materials, biographies of the the scientists, notes on past interviews and subjects of interest, references, and video clips - lots of them, and a new one is produced each week.
The SciFri blog
Science Friday podcasts
Science Friday videos