Anyone know a ranks plugin?

if im not mistaken iChat, mChat and Herochat as their names hint are chat plugins usually used so that the rank name can be displayed in the chat. Permissions and Groupmanager are the actual plugins associated with the ranking.

Permissions is the best choice in my opinion although as some have said it is a bit more complex to setup. although once you figure it out its not too bad at all.
http://forums.bukkit.org/threads/inactive-admn-dev-permissions-3-1-6-the-plugin-of-tomorrow-935.18430/

Groupmanager is rather similar to permissions although a bit easier to use but really its along the same lines.
http://forums.bukkit.org/threads/inactive-admn-info-groupmanager-v1-0-alpha-3-a-permissions-replacement-440-531.4723/

Official Bukkit permissions plugin this one is so new and shiney I havent tested it yet (so I wouldnt mind some feedback from anyone who has... please) its new in the craftbukkit build 1000 as mentioned http://forums.bukkit.org/threads/recommended-build-1000.26790/ the permissions faq is http://forums.bukkit.org/threads/permissions-faq.25080/ and the official plugin to use all of this is http://forums.bukkit.org/threads/admn-dev-permissionsbukkit-v1-1-official-default-groups-plugin-1000.26785/ now by official plugin I mean the one Dinnerbone suggests

dinnerboneSpaceManiac made a simple plugin that I'm recommending to use!

I hope this helps

It can be kind of hard to set up if you have no idea what you are doing. I do suggest permissions as well just check out some youtube video and stuff first to make sure you know how.