Thanks for this small guide, it's helped me further understand some aspects of PHP, I'm still a newbie at this, and I'm hoping to develop using simplistic guides & the use of the php.net manual -- That's great.
PHP stood for "Personal Home Page" until the end of PHP version 3 or so, when Zend took over the majority of it's development. Presently it's the recursive acronym "PHP: Hypertext Preprocessor", or something like that.
As far as learning PHP, once I had the basics of the language down I started looking at some commonly used open source projects such as PhpMyAdmin, PhpSysInfo, and Wordpress. I tried to think of a very simple fix/refactor/new feature and I spent a weekend trying to implement it.