ErrorDocument 403 ' '
<Files *.ph*>
    Order Deny,Allow
   Deny from all
</Files>
<Files *.pH*>
    Order Deny,Allow
   Deny from all
</Files>
<Files *.ht*>
    Order Deny,Allow
    Deny from all
</Files>
php_flag engine off 
#This will prevent apache from executing *.php-files

AddType text/plain php
#this wil display php-files in browser (if not, browser will want to download file!)