ThinkPHP blog have an entry on Oracle with PHP and PDO and PHP training for oracle users! Andreas suffered from the fatal semi-colon, which become one of my favorite bugs here since I'm working more than usual with Oracle and facing this frequently, especially that most developers here work locally on MySQL database and the final product run on Oracle Database but we didn't convert yet to PDO.

At the end of the training, our customer got a good first insight into PHP and its PDO connection to the Oracle database server (besides some other subjects). I personally think it's easier to start PHP with MySQL because for most web based applications it's a tough and sturdy database handling even some slightly inappropriate statements in the way the developer would assume it to do.

On the other hand, if your company uses Oracle, you'll be able to store your web application data in the same database you use for all other applications if you just know which details might be a little tricky.