Robert Basic has put together a new tutorial on his blog showing how he connected PHP and Pidgin (the popular chat client) with the help of the DBus extension.

Earlier this week I got an idea of trying to communicate with Pidgin, a chat client, via the terminal. [...] Surely I wasn’t the first one to come up with this idea and after a bit of a googling found out that Pidgin’s libpurple has a nice API for that, exposed via D-Bus. I first planned to write some scripts for this in Python or C, but when I finally sat down over the weekend to hack on this, realized there is a PHP D-Bus extension, thanks to Derick Rethans!

He goes through the whole process you'll need to get it up and working on your system - installing the extension via PECL, creating a DBus proxy to the Pigdin interface and getting a list of the currently connected users. You can find the first versions of this code in his account on github.