In reply to:

P.S. There's that song on the radio again -- "Amazing Grace" sung to the tune of "House of the Rising Sun". What's that all about?

Isn't it great? The group that sings that one is The Blind Boys of Alabama. I had the great fortune of seeing them live as surprise guests at a Ben Harper show I saw at the Greek Theater in Berkeley a couple years ago. I highly recommend them if you're into that style of music.