1)i want to make it, so that if someone registers, they have to be okayed by the admin - sort of like accepting/refusing comments/images but for allowing a person to be able to gain access and register.
is this possible? and how/where?
The first part is moderation. Admin must approve all a users images and coments. As far as registration NO that is a global option. Although you could alter your registration email text and let a registered user know of your rules. Then set the initial regular usergroup to no permissions except viewing. Create a new usergroup APPROVED. Place all your users in that group and set them the permissions you want. Then when someone registers go approve them by moving them into the approved group so they can post comment etc.
2)in edit usergroups there is an option to allow moderation. what is allowing moderation?