http://www.vubb.com
vuBB™ is a lightweight PHP Based Free Forum Software. It provides user group support as well as group permissions for security. Installation is not too hard but seeing as it's PHP and requires MySQL as the database engine, the configuration prior to installation can be quite a pain for those people that are not experienced with those 2 software products. Additionally, as of this time, the project is no longer being updated for fixed. Several of the community members have started to redesign it into a new product.
- Language System, easily change the forums language with the use of language packs