Hi there fellow Zergs!
Here's a little something:
http://raa-media.nl/blog/starcraft2/zvp-fall-of-first-born
I found that link on TL.
I've just started using that mindset on ladder so i doesn't mean mcuh (especially in diamond league) but i'm 4-0 against P so far, and those 4 wins were against strats i almost always lose to. It smashes every single midgame push and the guide explains anwsers for a shit ton of other scenarii and strats, some of which i had never heard of^^.
Just give it a try =)