Ok here is what I know:
-The new world is an all new map accesible by a /warp-like command.
-All items, rank, and money will be transferable.
-Just because you are a member, doesn't mean you have to use the new world.
-No player built towns, house, or any other structure will be moved.
-There will be a new /spawn and /warp market
This is all i really remember, post any rumors and I will try to confirm/deny them.