HTML is all you need to know (sure, you don't need it, but you can't display all that much without it)
http://www.php.net has the complete PHP manual - every function, operator, language construct, you name it, plus thousands of user comments which are very helpful. Hands down THE BEST php resource out there, especially considering it's maintained by the makers of PHP and is free.
http://www.devshed.com/Server_Side/PHP - Devshed has a good PHP tutorial for beginners - scroll down towards the bottom and work through the PHP 101 series. I found it to be a good transition to the php.net manual, which may seem a little daunting if you're just starting.