Sullo writes in

"CMS Explorer is designed to reveal the the specific modules, plugins, components and themes that various CMS driven web sites are running. It can also search OSVDB.org for vulnerabilities in found components, as well as "bootstrap" a security proxy by downloading potential file names from the component's code repository and then requesting them directly from the target.

CMS explorer currently works with Wordpress, Drupal, Joomla! and Mambo."

Download: http://security.sunera.com/2010/03/cms-explorer-or-whats-that-cms-running.html