You had also asked about PHP. PHP is a scripting language, and probably the most common use of this language is to provide access to a backend MySQL database (MySQL is a free open-source database), and serve up its data.

You'll notice that folks who use PHP and MySQL have web pages that have a '.php' file extension. You can look at an example of what PHP can do on the following pages:

1. Boston Irish Pubs - here is a a page that utilizes PHP, MySQL, and Google Maps to serve up the location of Irish Pubs across Boston. The location, and all the details for each pub are stored in a MySQL database, and PHP is utilized to access that data, and serve it up to the visitor.

2. Boston Condo Developments - here is a page that, again, utilizes PHP, MySQL, and Google Maps to serve up the location of various condominium developments in Boston.

Hopefully this gives you a little insight into the power of these technologies.