Have you guys considered a bulletin board, (could be a regular forum) where you could post announcements on
changes to the site? I think that would be
good, and if you could give the members a little heads' up, in the form of a banner on top (like you use for when the site will be down) that there is new info on site changes on the bulletin board....that would be good. It's sometimes easier to adapt when you kind of know what you're looking for. I think it's a good idea!!