Bukkit

EnChat connects your server to the JereNet, specifically the JereChat service
[, which is a chat protocol/service that supports flexible entry points (In a similar way to IRC)].
This allows you to customise the chat on your server. You can also link chats across differrent servers in managable channels, as well as offering embeddable webchat applications etc.

• Because of this you can share the same chat across multiple servers (I.E. Huge Servers or Clan Servers with multiple modpacks etc.).
• With EnChat, you are also able to customise the appearance and behaviour of your chat to a very high extent.
  (Using the same syntax as command blocks, so it is very easy to learn!)
• You can also stay in touch with players on your server without being in the game, via a webchat, offline clients or scripts for other environments (I.E. ComputerCraft)

You can view some examples at
http://dev.bukkit.org/bukkit-plugins/enchat/pages/documentation/examples/

Or you can download the latest version here {dev}
http://dev.bukkit.org/bukkit-plugins/enchat/files/

GitHub
https://github.com/TheJeremail/EnChat

Note:
By default, this plugin will connect to the main JereChat node (https://jerechat.cf).
In the future (for better performance) you will be able to host your own nodes! (Hence the config option)

Note:
Contrary to some peoples belief, you do NOT need an account at http://thejeremail.net it is OPTIONAL. If you do however have one, with an Identical username, or you would like to use your JereNet name to chat, you can do so. The same goes for the server's agent.

Note:
The webchat application will also allow moderators/ops (From ops.json OR set JereNet usernames) to execute commands etc.