I've been wanting to read more of David Lewis, and I recently learned via his entry on the Stanford Encyclopedia of Philosophy that he wrote a handful of essays on philosophy of religion, despite the fact that he didn't have a religious bone in his body. Here are links to them, courtesy of Andrew Bailey's Lewis page:
"Anselm and Actuality" (with a postscript from Lewis's Philosophical Papers, vol. 1)
"Evil for Freedom's Sake"
"Do We Believe in Penal Substitution?"
The only one I've read so far, and only part of it at that, is "Divine Evil". Thus far I am underwhelmed and disappointed. Lewis first states his support of the logical problem of evil, something most philosophers have rejected since Plantinga wrang it through the wringer about four decades ago (contemporary arguments tend to be probabilistic arguments from evil). Then he goes on to say he won't be addressing the philosophically sophisticated concepts of God but the simple concept as held by the common religious practitioner. In other words he is self-consciously attacking a straw man. The simplistic concept of God that he addresses is that God sends people to hell for not guessing correctly as to which religion is correct, if any. But I very much doubt that even a simple-minded Christian would agree with this picture. Part of the concept of God in Judaism and Christianity -- in both the simplistic and sophisticated pictures -- is that God is just. He wouldn't send people to hell for failing to respond properly to an alternative he never really presents to them. Pascal wrote that God has given evidence which is sufficiently clear to convince those whose hearts and minds are open to him, but which is sufficiently vague so as not to compel those whose hearts and minds are closed to him. With all due respect to Lewis, I think he fell in the latter camp.