These are some of my favourites web site about PHP. Links about other arguments are listed in main MENU -> LINKS section.
the official website is the best place where you can start; search here first if in doubt
phpMyAdmin is one of the best tools to manage MySQL database on the web, written in PHP: essential
the first problem of the PHP newbies is how to protect the source code; my opinion is that this is not the right starting point to approach open source programming; anyway this is a tool to optimize (cache) performances and protect your source code too
official web site, updated manual and downloads
“Apache has been the most popular web server on the Internet since April 1996. The November 2005 Netcraft Web Server Survey found that more than 70% of the web sites on the Internet are using Apache, thus making it more widely used than all other web servers combined.” You can solve most problems “fine tuning” Apache configuration and its modules (as PHP!)