Faced a weird problem after installing Apache 2 and PHP 5 on my Ubunto 10 machine today. The browser was giving an option to download the page whenever I tried clicking a PHP page link. Clearly the PHP was not getting executed properly by Apache and it was treating it as an unknown file format.
After a couple of hrs figured out this solution.
In httpd.conf file, add following lines
<IfModule mod_php5.c> AddType application/x-httpd-php .php .phtml .php3 AddType application/x-httpd-php-source .phps </IfModule>