One of the very best resources on the Internet, IMO, is Kevin Yank's Website: SitePoint.com. I have been a long time subscriber to his news letters and have several of his books. I'd like to recommend that you bookmark his site and visit it often. The resources and forums are invaluable, imo.

In particular, I highly recommend his PHP and MySQL Tutorials section. There is such a plethora of information in that section. Plus, he even generously prints many chapters from the books that they offer! Get over there ASAP and start learning, improving, and honing your skills!