I do web sites, but unfortunately I do not know anything about managing a group of people. Please let me know if this is not the right forum of where to post this question.

I need something that helps to organize a set of charity working groups around a open source or free collaborative platform.

I do not know if it is recommended that they use some of the communities portals that are around like MySpace, Bebo, Facebook, etc to create their group, or an open source software that runs under linux shared server.

Can somebody suggest something good and simple to use, with chats, forums, calendars, events, galleries, perhaps projects?

Any insight is very much appreciated.

Best regards