I sent a late-night query to PMA back in November '07. I received a response within minutes from Peter himself, telling me I shared a surname with his mother, so of course he wanted to read my book. I was then directed to his website for how to proceed.
His website mentioned something about expecting writers to follow the industry standard (?!) of exclusive submissions, or something along those lines, so I emailed him back to let him know the book was already out with other agents. He got back to me same day requesting I FedEx the ms right away, and when I returned home that evening I discovered he'd left a phone message as well.
I sent the book FedEx as requested, and some time later recieved a call from him on my cell phone. He wanted to know whether he'd emailed me. I told him he hadn't, which seemed to surprise/annoy him. So, he said he would and ended the call without saying anything about what the email would be about. What followed was a fairly long email exchange in which I had a very hard time decifering what I was being asked to do, but finally determined it was a request to revise and resubmit the first 60pp, so I just went with that. I never heard anything again. Status queried maybe a year later and was directed (and cc'd) to someone else, who responded to the cc with the information that I'd been rejected some months before.
My experience with Peter was maddening at times, but I have to say, I really sort of liked the guy. He certainly does things his own way, and I probably wouldn't have a hair left on my head if I ever worked with him, but he's kind of fun. He's definitely not a "While your work has merit, I did not connect with your story as much as I had hoped to... Subjective business, blah, blah, blah" kind of a guy. I met one of his clients at a party last year, and she seemed to genuinely adore him.
YMMV.