Messages replaces your boring /w and /msg with a more fancier and polished interface, that is easy to use and familiar.

Messages offers instant messaging, since it goes straight through the server, onto the other person's end, so you can have a seamless conversation.

Messages Screen:

Messages Screen

You can also message offline players as well, and they will receive their message as soon as they log on.

If your friend isn't on the screen at the time, they will receive a notification of your message:

Notification Screen Required on both client and server.

Dependencies:

Addditonally you can find the sources jar as a secondary file in the versions.