On the SitePoint PHP blog they have a post that "reintroduces PDO" or as they describe it, the "right way to access databases in PHP". The PDO functionality in PHP provides extra handling around database connections and queries as well as making it easier to connect to multiple types of databases with similar code.

PDO is the acronym of PHP Data Objects. As the name implies, this extension gives you the ability to interact with your database through objects. [...] PHP is rapidly growing, and it is moving toward becoming a better programming language. Usually, when this happens in a dynamic language, the language increases its strictness in order to allow programmers to write enterprise applications with peace of mind.

In case of PHP, better PHP means object-oriented PHP. This means the more you get to use objects, the better you can test your code, write reusable components, and, usually, increase your salary. Using PDO is the first step in making the database layer of your application object-oriented and reusable.

He starts by answering the question most ask about PDO versus mysql/mysqli by pointing out that PDO is more OOP friendly, it allows for parameter binding and the fact that the mysql extension is no longer supported. He shows how to check and ensure PDO is installed on your setup and, if not, how to add it in (for both linux and Windows systems). The tutorial then walks you through using PDO: making the connections to the server, running queries and returning the results. This includes a section on prepared statements and bound parameters and their benefits including SQL injection prevention.