Moodle is a free, open-source PHP web application for producing modular internet-based courses that support a modern social constructionist pedagogy. You can read more about it at www.moodle.org.

Moodle Pty Ltd (also known as Moodle Headquarters or the Moodle Trust, based in Perth, Western Australia), an Australian company who perform the majority of the development of the core Moodle platform.