Tuleap Open ALM is a Libre and Open Source software forge crafted in PHP/MySQL. Development occurs in realtime on http://tuleap.net You can find mirrors on Github
Use case, screenshot & more on http://tuleap.org.
You should follow the installation guide available on tuleap.net.
The tuleap-devel mailing list will be more than happy to help you to get the most of the software, don't be shy we are nice with new comers.
You can start looking at the tuleap developer guide and of course you should subscribe tuleap-devel mailing list.