DevShed is getting back to basics with a new series it's started - a beginner's guide to programming with PHP. They've already posted part one:

PHP has been taking the web by storm because of its power and versatility. If you'd like to add PHP-based applications to your web site, keep reading. This series of articles will teach you the language from scratch.

They start with a mini-history of the language to get the budding developers out there warmed up. From there they move into some of the foundations of the language - what it was created for, the kind of functionality you'll find inside it and a first trip into variables (specifically strings).