Just reading back this topic and I can't believe it's already months ago that this was posted. We definitely could use some clarification on this. I asked on bitcointalk about this, but didn't really get a reply.
So "Pay To Preach" basically means: everything that has to do with spreading the Gospel where funds are a welcome thing.
So: BiblePay University, Letter Writing, Quizzes? Any more suggestions?
Paying people to talk about BiblePay (but that's maybe more PR)?
Maybe P2P and PR could be merged in the future?