So I've upgraded to Mavericks (or maybe Yosemite) yesterday but now I only get a view of my directory when I visit localhost but the included index.php isn't executed anymore.
I have to uncommented the virtualhosts line in /etc/apache2/httpd.conf
# Virtual hosts
Include /private/etc/apache2/extra/httpd-vhosts.conf
so my virtual hosts work but php doesn't get executed.