SimpleMailBox:

SimpleMailBox is a plugin that allows players to create mailboxes. People can make books and put them in these mailboxes. If a player goes offline and they have a book in there mailbox when they come on later they will be notified that they have mail. Players can not destroy other player's mailboxes. This plugin is great if you want to add a social aspect to your Minecraft server!
How to make a mailbox:
Mailboxes are quite easy to make. You put down a fence and put a log on top of it. This will create a mailbox for the player. The player, if they chose, can delete their mailbox by breaking it.
How to give a book:
Make a written book and sign it and come up with a title, if the title exists in there mailbox already it will write over the books.To give a book go to the player's mailbox with the written book and left click the log. And the message is sent.
Going to add
Features:
- Works in the Nether
- Mult world support
Permissions:
Commands:
ChangeLog
Admins:
http://dev.bukkit.org/bukkit-mods/simplemailbox/pages/how-it-works/