take a look also at the following if they fits your needs
(the first two are italians, and they lack english documentation, sorry)

http://www.archimista.it (ruby on rails)
https://github.com/codexcoop/archimista

http://www.xdams.org (java)
https://github.com/xdamsorg

http://collectiveaccess.org (php)
https://github.com/collectiveaccess



--
raffaele, @atomotic