The show is called Musical Starstreams. I don't know how you'd describe the music... It's ambient music, very chilled out, spacey and atmospheric. It doesn't crescendo and most of it is instrumental. It used to be on WNUA from 10 pm to midnight every sunday. Most (but not all) of the artists are from the UK and are very obscure.
A perfect example of Starstreams music is the group Tangerine Dream. I'm sure everyone recalls this song from a very popular 80's movie. The song is called Love on a Real Train. Once you hear it it'll be easy to recall the movie...
Tangerine Dream is a great instrumental group and has tons of beautiful moody tracks like this one.