Professor David Malan of Harvard University gives lectures on YouTube about PHP scripting language and many other areas of interest. I watched a few of his PHP lectures and they were loaded with useful information that few could understand after watching it only once.
If you have an interest in PHP I suggest you watch these videos. However, you should have prior knowledge in HTML and CSS because those languages are incorporated into PHP to structure and dress the page behind the function you're completing. PHP tells things to happen within the HTML pages such as "accept form field" and "place form field here" once submitted. Facebook uses PHP commands to accept your posts, likes and personal information updates.
I understand bits and pieces of Professor Malan's lectures, and I plan to watch them again to see what I missed. I like how he wears shorts during his lectures, I guess I thought there would be a dress code there.
The 1st lecture is posted below and there are a few more YouTube links below that direct you to his additional lectures on PHP.
Professor Malan lecture 2: http://www.youtube.com/watch?v=TbhUCY2NmZE
Professor Malan lecture 3: http://www.youtube.com/watch?v=wdAfILoJWcI