In a quick note from phpPatterns.com this morning, there's an announcement concerning ArgoUML and PHP.

ArgoUML, the Open Source modelling tool from Tigris now has PHP support. Still experimental but good news for anyone hunting for a PHP modelling tool. You can get the files from http://argouml.tigris.org/servlets/ProjectDocumentList.

With a few minutes playing managed to get it up and running with the Java 2 1.4.2 SDK (docs say it should work with 1.3+).

[...] Currently seems to have support for generating PHP code from UML (but not vice versa).

Lost as to what UML might be good for? Well, UML, the "Unified Modeling Language", allowss you to generate an organized overall view of your application, ensuring that every need is met and each path the user might take is covered. For more information, check out the other resources on UML.org.