Here's a BBC News article (http://www.bbc.co.uk/news/magazine-30512620): Neil Gaiman writing about the writing of Good Omens. For those in the UK, it's just been adapted as a radio play, to be broadcast in episodes this week, and available on the BBC iPlayer.
I'm sure I've heard about this before somewhere, it definitely felt familiar, caught the double bill last night and decided I'll continue with it, enjoyable so far