Basically all of the select/chunk/region-based protection plugins will do this: http://dev.bukkit.org/server-mods/?category=anti-griefing-tools&search=protect I use Residence, I like the configuration options and how players can set specific flags for each area/subzone without admin help.
I don't think so. The region/area based ones usually have a 'use' flag of some kind that allows/disallows the use of buttons/levers/etc for player groups/players.
Sorry I'm not familiar with that plugin and the wiki listed on dev.bukkit.org/server-mods/izone/ has a 404.