Permissions
Tested with PermissionsBukkit, there are four permissions:
General
Allow players to change a villager's profession
profession.change
Allow players to change a villager into a zombie villager
profession.zombie
Admin/moderator
Allow players to set materials using /setprof
profession.setprof
Allow players to toggle Profession on/off in a world using /worldprof
profession.world
Allow players to toggle material consumption on/off using /consumeprof
profession.consume