Here are some helpful links for your journey with web development and PHP programming.

Description Link
The official PHP manual
* A great resource for learning PHP. I recommend everybody sit through this at least once.
An online primer for PHP. It enables you to run PHP code inside the browser, which is pretty helpful for trying your own code out.
When you're a little more advanced, and would like to learn things like best practices, and modern trends.
For visual learners, a collection of around 200 videos on PHP
* A great tutorial on Regular Expressions is a great place to learn web development, and other programming skills. Just as another example, here is a link from the site where you can brush up on your HTML skills
The codeigniter website
A great tutorial for PHP
A great, interactive tutorial on SQL