The ##php IRC channel on freenode (1) is an absolutely incredible resource. I've idled in there for many years now and the amount of good, relevant, and accurate information that can be obtained in there is incredible. Whether you have been programming for 5 days or 5 years, simply hanging out in the channel for a couple of days can offer insights and tricks that you may have never known about.
Over time, the folks there have compiled an absolutely excellent Wiki (2) for developers; old and new. In addition, there is a wonderful list of general do's and don'ts for PHP application development. (3)
Time and time again, we get folks in there who are using outdated technologies (hello mysql_* functions) or just awful tutorials or resources and they get turned around in no time.
Disclaimer: as the author states, there are many self-described experts in PHP and they do, occasionally offer bad advice. However, it is rare for the bad advice to go unchecked in this IRC channel so I can still recommend it without worry.
[1] - http://freenode.net/
[2] - http://wiki.hashphp.org/Main_Page
[3] - http://hashphp.org/