It is obvious that the two systems are different, so we are going to try to make the move as easy as possible -- there are some significant changes in BE Communities, but having worked with quite a number of folks (internally AND externally) leading up to what exists now, what has been done (so far... we are by no means done) is in the best interest of the site's members.
That said, in the Everything Else Forum is this post that describes the "transition" of the public discussion groups (way too many of them, IMnsHO) to BE Communities Forums. We will be dropping breadcrumbs in the discussion groups when we are ready to "announce" these Forums publicly to make the transition really easy. Another alternative to all that is to simply go to the BE Communities Forums, open the appropriate/respective Forum Group (e.g. Products, Solutions, Communities, General, etc.) and then do a <Ctrl>F to locate the area(s) of most interest to you.