Um... user user-agent DOESNT NEED TO SUPPORT PHP.
The output of a PHP page is no different from the output of a plain HTML page, you dont' need to do ANYTHING to get a PHP page to display on a Blackberry, we do it ALL THE TIME!
PHP is SERVER-SIDE, the Blackberry will not ever even know that the page is a PHP page, to it, its jsut HTML like everything else ( ASP, Perl, Java, C CGI, etc. )
edited cause i ucked up :-)