PHP Help :

Dreamweaver CS3 and CS4/ Windows. 

This extension installs the PHP Manual in CHM format with two options to use it:

 

The first one is a button installed in the "PHP" tab within the insertbar.  The second option is right-click your mouse button. In the contextual menu you will find:"PHP Function Reference...". Select it and the help will be opened.

 

 

In both cases, if you have previously selected a function name, the page where that function is explained will automatically be  opened.

 

If your selection is not a function name, a prompt message will you inform about it and will ask if you still want to open the PHP Manual

 

Thanks to French site FlashXpress, there's also a tutorial about how this extension works in French
Current version 7.1.0 (updated April 21, 2009): Version Compatibilities Dreamweaver MX PHP Help 5.0.2 (Discontinued due to issues with current chm files from php.net) Dreamweaver MX 2004 Dreamweaver 8 Dreamweaver CS3 / CS4 PHP Help 7.1.0 (Download, 6MB) (Notice: You will have to remove previous version if you are upgrading).   Version 7.1.0 has the chm file included, please read the post in my blog explaining the reasons for this.