Thing 21

I haven't made a podcast myself, but there are several on the Darwin Correspondence Project's website.
There's one about the dramatisation of the correspondence - called 'Re:Design' - at

http://mediaplayer.group.cam.ac.uk/component/option,com_mediadb/task,play/idstr,CU-CSF-PC07-05_DarwinCorrespondence/vv,-2/Itemid,57

There are also interviews about Darwin and his relevance today which can be accessed from this web page

http://www.darwinproject.ac.uk/commentary

Like a lot of things, the more effort is put in, the better the final product.