Take a look here: http://www.vdash.org/
This is a project just like yours, IMHO. But I guess there are many similar projects here and there; wiki software is free and there are plenty of "not wikimedia" implementatios, covering vatious fields of knowledge & interest.
(Saluti anche in italiano.... homscritto inglese perchè tutti i membri della lista possano leggere :-) )
Alex