I'd like to bring your attention to some wonderful comments from blog listener James who recalls hearing "Suspense" on Armed Forces Radio and a bit about how the BBC created their own series that was similar to "Suspense".
If you haven't read it yet, I recommend checking out a recent report from the Library of Congress on how copyright and ownership issues are causing difficulties for libraries and archives in preserving audio recordings. (Boingboing and other blogs have featured posts about the report the past few days.) Of particular interest is the section on old time radio, where they outline issues with how original recordings are so widespread and dispersed among institutions and private collectors. They also outline the many copyright and intellectual property issues faced by institutions and collectors when dealing with the material.
You can download the entire pdf document (1 mb) here - the old time radio section starts on page 29. The report is free for download or $30 for a printed copy.