Moodle is a software package for producing Internet-based courses and web sites. It is a global development project designed to support a social constructionist framework of education.
Moodle is provided freely as Open Source software (under the GNU Public License). Basically this means Moodle is copyrighted, but that you have additional freedoms. You are allowed to copy, use and modify Moodle provided that you agree to: provide the source to others; not modify or remove the original license and copyrights, and apply this same license to any derivative work. Read the license for full details and please contact the copyright holder directly if you have any questions.
Moodle can be installed on any computer that can run PHP, and can support an SQL type database (for example MySQL). It can be run on Windows and Mac operating systems and many flavors of linux (for example Red Hat or Debian GNU). There are many knowledgeable Moodle Partners to assist you, even host your Moodle site.
