you will need to have root access to edit the httpd.conf,
there is no way to do otherwise
whoever compiled php, if they read the INSTALL file they would have noticed
that they need to uncomment
AddType application/x-httpd-php3 .php3
#AddType application/x-httpd-php3-source .phps
#
And for PHP 4.x, use:
#
AddType application/x-httpd-php .php
AddType application/x-httpd-php-source .phps
i would think this would be your problem if you have mod_php.c compiled into apache
regards