@edgarblythe,
Try X-Minus One, a half-hour science fiction radio drama series broadcast from April 24, 1955 to January 9, 1958 on NBC.
DOWNLOAD HERE:
http://www.archive.org/details/XMinus1_A
The first 15 episodes of X Minus One were new versions of Dimension X episodes, but the remainder were adaptations by NBC staff writers, including Ernest Kinoy and George Lefferts, of newly published science fiction stories by leading writers in the field, including Isaac Asimov, Ray Bradbury, Philip K. Dick, Robert A. Heinlein, Frederik Pohl and Theodore Sturgeon, along with some original scripts by Kinoy and Lefferts.
Included in the series were adaptations of Robert Sheckley's "Skulking Permit," Bradbury's "Mars Is Heaven," Heinlein's "Universe" and "The Green Hills of Earth", " Pohl’s "The Tunnel under the World," J. T. McIntosh’s "Hallucination Orbit," Fritz Leiber’s "A Pail of Air" and George Lefferts' "The Parade."
http://en.wikipedia.org/wiki/X_Minus_One
Have over a 100 30 minute episodes on my Ipod