MySQL is your database system, PHP is your programming language and most likely Apache is your web server software, based on Linux server. (Read up on LAMP to get an idea of how it all fits together....
LAMP (software bundle)) - Wikipedia, the free encyclopedia. Alternatively, you could be running MySQL and PHP on top of Microsoft Windows IIS server, but if you did, you'd probably be using ASP instead of PHP.
What kind of pointer are you after for MySQL?