There are so many IDE's that based on Eclipse platform, and countless projects have been crafted in Eclipse IDEs. For PHP development this is Eclipse PDT (PHP Development Tools) project.

Eclipse PDT was developed jointly by IBM and Zend, although participators come from beyond those two organisations. Not long ago, Aptana (whose Aptana Studio supports PHP) has begun significant contributions to the PDT project.

Eclipse PDT is available for Windows, Linux, and Mac OS X. Windows and Mac OS X versions can be had in 32-bit or 64-bit variants.

We tested the Windows version of PDT, an "all in one" installation that bundles every plugin you need for PHP development and then some. This includes the Data Tools Platform for managing databases, as well as plugins for JavaScript development, web development tools, XML editors and more. Eclipse PDT also includes the Zend debugger, though you can use Xdebug as well. Of course, if the preinstalled features aren't enough, you can install any useful plugin from the vast spectrum of Eclipse development tools.

As with any multilanguage IDE, Eclipse PDT's documentation can be difficult, and it only gets worse as you add plugins. You can't blame that on the IDE, though. On the plus side, all the documentation is available in a single, searchable interface.

Link to the official website: http://www.eclipse.org