"PHP is a widely-used general-purpose scripting language that is especially suited for Web development and can be embedded into HTML. PHP is mainly focused on server-side scripting and can do anything any other CGI program can do."
"MySQL enables organizations to cost-effectively scale-out their database infrastructure so they can exponentially grow their web-site traffic and transaction volumes. Leading organizations are saving over $1 million using commodity hardware and open source software."
More info at: http://www.php.net/ & http://www.mysql.com/