Me and a few others are starting up a scientific wiki encyclopedia called WiSci. Think WikiPedia focusing on science, and you'll get the gist, with the main difference being a (yet to be formalised) policy of peer-reviewing articles before semi-locking them, in an attempt to get a higher level of accuracy than WikiPedia currently has, whilst still allowing for the addition of new information to the articles.
Anyone can join up and create/edit articles, so if any of you computer gurus would like to come along and work on some computer-science articles, you'd be more than welcome
www.wisci.org