Gary13579: That's not what he asked for. He wants to be able to approve new registrations, that's all.
ifrit: Currently not. However, once PunBB 1.2 is released, you will be a few steps closer. It won't have the functionality "out of the box", but you could setup the forums so that new users are placed in a user group with very restricted permissions. Then create (or have someone else) a simple plugin for the admin/moderator interface that lists users in that user group and gives admins and moderators the ablility to assign them to a proper user group. Just a thought.
"Programming is like sex: one mistake and you have to support it for the rest of your life."