Additional PHP Documentation
I have found PHP documentation on the web to be somewhat superficial. It does not generally get very involved at showing complicated functionality. I have tried to include somewhat more complicated functionality here, however more is required.
For additional documentation, see the PHP weblinks section. I will post good links as I find them. Also there is a PHP manual at PHP.net documentation section. It is in downloadable PDF fomat along with HTML format. It is worthwhile as a reference and gives some code examples, but does not seem to include much detail with regard to the language and how it works. It does have an excellent library reference of PHP functions.