Scalability and large site issues

Hi I need to persuade someone of the superiority of php vs asp vs java. I appreciate that these sort of questions get asked all the time but I cannot find an answer to my particular question in the mail archives. If an application grows in asp then you write a COM object and port the code to the COM object (which is compiled and therefore more efficient) to do the work. In JSP you would use EJB to build the server side components. The above two sets of technologies appear to be tightly integrated into each other. My question is this. If I am writing a PHP application, what enterprise level server side technology should I be using to make the site more scalable? Does PHP work well with any other particular technology? or is it the case that it can link in well with many differing technologies, thats what makes it so attractive? I need to look at a strategy for very large scale sites. Will PHP cope or will I need to use PHP and something else? If so, what is the something else? Thanks for listening Gary