Just up the road from us in Oxford there's an invitation-only workshop going on as I write this. It's about cosmology and the multiverse.
I've been following live blogging from one of the participants, Sean Carrol. Check out: day one here -- day two here -- day three here.
Turns out that there are quite a few multiverses:
1. The 'pocket universes' of eternal inflation.
2. The 10500 different false vacua of the landscape resulting from variant 6-dimension compactifications onto Calabi-Yau manifolds in string theory.
3. The 'many worlds' in the MWI of quantum mechanics (Everett, David Deutsch et al.).
I think it's possible, and maybe even desirable to believe in all three of the above at once!
Here's the PDF briefing paper for the workshop.
Update: Apparently this workshop is being funded by The Templeton Foundation. Explains the otherwise mysterious intrusion of The Deity into the proceedings. I feel sorry for the mandatory Philosopher of Theology present: the physicists seem to have hijacked it ...