How to go from free to pay only on an established forum?
 

We're trying to go from an established, free forum over to a pay-to-view forum. The question is - how to take current users (registered) and port them over to paid (paid). I've read some of the posts that I can find as far as setting up a new user group, but don't know where to go from there. Something about an administrator announcement and make one forum that the non-paid can see and place the directions in that? Will I need to port them over from registered to paid manually?

I know this move has been suicide for some forums before, but we are in a niche market and feel that we can pull this of successfully. We're not looking to make millions - it'll be $25 per year. Besides, the amount of hackers and spam we get is sickening (takes hours to police) and perhaps it will help with this as well as we don't have the manpower to hire a dedicated moderator.

TIA!