I personally would suggest a simplemachines forum. It's a great hosting site; both Insimenator and TwoJeffs Simbology run on that. Of course, from what I have seen there doesn't seem to be much in the way of formatting ability, and I am also unsure of the cost.
I also know of a free forum host, namely Proboards, though I am unsure of the bandwith/storage capacity.

Good to know GoS will be back soon!

Sincerely,
Misery