Hi. plugin is simple, to enchant an enchanted item: to enchanted item gives more enchants and upgrades the effect level example: sword (Loot I) >> sword (Loot II/III, Fire aspect I/IV...)
http://forums.bukkit.org/threads/fun-tim-the-enchanter-v2-0-enchant-your-items-1-2-3-r0-2.46310/ Like that?