A post at Transom.org titled Audio/radio art — sites of interest presents a collection of online resources specializing in radio and sound art. Subject areas include experimental radio and soundscapes.
Many of the spoken word creations transport you to imaginary sound spaces which have a dream like quality quite different from ambient music productions. An example being Garden Planet Revisited by Jacki Apple from the New American Radio archives.
If you want to start listening straight away try these streaming sites for an easy introduction.
New American Radio Helen Thorington’s excellent archive of the New American Radio series is a good place to start your journey. There’s a lot of material here so you may want to browse the audio for something you find interesting.Free103point9.org a 24-hour online radio station featuring works by experimental musicians and sound artists working with transmission mediums.