Permission- bukkit - minecraft, Permission(pex) is a new permissions plugin, based on permissions ideas and supports all of its features. but pex is more! it offers different backends, powerful.
Setting up groupmanager on your bukkit server, What is groupmanager, and where to get it in order to enable permissions on our server, we need to download and install a plugin. there are a few plugins that can.
Vault - bukkit - minecraft, Vault is a permissions, chat, & economy api to give plugins easy hooks into these systems without needing to hook or depend on each individual plugin themselves..