the project is to establish a [url removed, login to view] clone based on Jabber. I guess the best solution is ejabbered ([url removed, login to view]) and as client claros chat or JW Chat (which is included on ejabbered). But if you know better solutions just suggest...
For the ajax frontent you could combine the messenger with this or such a frontend: [url removed, login to view] It looks meebo like.
So at the end you should install a meebo clone which can be used in multilanguage - primarly German and English. Furthermore file sharing should be possible. Please check [url removed, login to view] for detailed features.
Thanks a lot.
P.S. Please tell me also the requirements for the webserver.