Admin Levels...


I've looked around and there are variations of what I'm looking for, basically, I want to be able to add a user to my site who is given certain Admin rights, but not all of them, for example, they would be able to authorise new membership requests, but not be able to change of any of the plugins, mods or site settings for example.

Anyone any idea if this already exists... if so, can you point me to it, cause I can't find it.

Thank in advance,