apt-get install php5
/etc/init.d/apache2 restart



allow to execute php scripts inside html page
http://forums.digitalpoint.com/showthread.php?t=7584


nano /etc/apache2/httpd.conf
##########################################
<IfModule mod_mime.c>

AddType application/x-httpd-php .php
AddType application/x-httpd-php .phtml
AddType application/x-httpd-php .php3
AddType application/x-httpd-php .php4
AddType application/x-httpd-php .html
AddType application/x-httpd-php-source .phps
</IfModule>
############################################