I would like to propose to use Drupal 6.3 for the website.
Drupal 6.3 features :
* Very good user interface, with almost all in one website (menu,
navigation bar, HTML editor, etc ...)
* Possibility to write collaborative manuals and books,
* Integrated translation interface (based on po files), one source
language, several target languages.
* Integrated forum, phpbbforum module allow the integration of existing
phpBB forums and accounts.
I think we could add web 2.0 features, such as "Publish your own
tutorial" and gather a very rich set of tutorials, then translated
content into several languages easily ... and beat competition.
Of course, I can help on such a project, especially for setup.