Does anyone know of any examples of this in terms of both front end (interface) and back end? Thanks for your time!
I don't know of any specific UI examples of this, but the simplest way to handle the back end would be to have a database column approved as a TINYINT(1), BIT, BOOL, or whatever boolean field your RDBMS uses.
Any changes from the user force the approved column to a value of 0/FALSE. The administrative approval queue merely has to select for rows WHERE approved=FALSE.