Things in Heaven and Earth

highly recommend it, listen to the radio on the main page for a while, find something weird.  it has the best folk recordings there are in existence.  folkways smithsonian anthology of american folk music is essentially the bible for anything to do with folk.  loads of primitive blues as well, and field recordings.

especially http://www.folkways.si.edu/explore_folkways/tapestry.aspx  check dose podcasts