Because of the dearth of audio books in Korean, I eventually broke down and bought an easy version of the Bible in Korean -- 쉬운성경 CD
It was expensive at 144,000원 but it was perhaps the best purchase I have ever made in my Korean study. It provides me with over a hundred hours of really clear audio and because it's the easy version it doesn't include archaic words or grammar but the normal idioms and phrases people are using every day. It's also cool because unlike other audio resources, it's actually was made for other Koreans not for foreigners.
What I've tried to do is have it playing as much as possible when I"m doing something else, and after listening to it ten times or so I find I can follow stories about Jesus or some of the old testament ones (such as Samson or Ruth) quite well.