The MIT Technology review just published an extensive article about P4P. It's a good read, but does not offer too many new details for people who have followed the discussion. Well, except this part, buried somewhere towards the end:

"Doug Pasko, principal member of the technical team at Verizon, says that Pandora and Verizon have plans to roll out a P4P implementation soon, possibly by the end of January."

I guess they meant to say Pando, not Pandora. In any case, we might soon have a chance to to see whether P4P is about ISPs embracing P2P or about subverting net neutrality.