There have been a couple of blog posts over recent months about the book A Canticle for Leibowitz, a famous example of science fiction exploring religious themes.
IO9 recommended a piece in the New Yorker which fills in the context against which the book was written.
And Speculative Faith shared a review of the book by Michelle Wood.
Of related interest, a Florida minister has expressed an interest in converting robots to Christianity. I hope someone recommends to him my chapter on Robots, Rights, and Religion” in Religion and Science Fiction!