how to do cloud computing with php

Hi.. As a way to take a few steps back from the kinda heated "when will php grow up and support threading" thread, i'm requesting you people list how you scale from 1 server to many servers; what's called cloud computing. In particular, i'm interested in how to set up an application that deals with great amounts of input from many 3rd-party servers, and say a million concurrent viewers who need html calculated from those input streams. So this goes beyond 1 mysql server, and beyond 1 php server. Let's hear it, coz quite frankly i have my doubts about php's ability to scale to cloud computing.