PHP_UML is a PHP parser, an XMI generator and a documentation tool.

Practically, with PHP_UML, you will be able to feed a UML CASE tool, like
Rational Rose or Argouml, with a UML representation of existing PHP source code.
This way, you get an instant overview of a PHP application, with all the usual
functions of a software design tool (such as class diagrams exportation,
refactoring of object-oriented applications, or automatic code generation).