Ning No More? Need ideas for networking sites

I lead a group for artists at my church, and we’ve been using a Ning network to keep all our members connected. But recently, Ning announced they were ending their free networks. We can’t pay for this service, so we have to find a new online home.

We’ll probably migrate to a Wordpress page, or default to our Facebook group until we figure things out. Meanwhile, I’m researching our options. Obviously, this here GWC forum is one great model I could go with, so how does one go about setting up such a thing, and what are the costs involved–both money and time?

Or does anyone know of a free, Ning-like site where we could restart something similar to what we have now?

Felica Day was concerned about this. Her crowd-sourced conclusion.