Why would you like Apache to ignore PHP files ? Anywho, remove the lines in your httpd.conf that specifies Apache to let PHP interpreter handle the file types php.*
ie ;
<IfModule mod_php4.c>
AddType application/x-httpd-php .php .php4 .php3 .phtml
AddType application/x-httpd-php-source .phps
</IfModule>
<IfDefine HAVE_PHPCGI>
AddType application/x-httpd-php .php .php4 .php3 .phtml
AddType application/x-httpd-php-source .phps
Action application/x-httpd-php /pub_cgi/php
</IfDefine>
Hope this helps