Bukkit

JoinMessageChanger

BetterJoin

QuikAnnounce - Announces things on the fly!

Allows players to get the time by simply typing 'thetime'

Allows you to customise, interlink or externally access the chat on your server.

Allows an admin to broadcast a message to all players.

Replaces the bland "Player has joined the game!" and "Player has left the game!" with a more colorful version.

An easy way to setup automated announcements on your server.

Chat with a command, and only players with permissions will hear what you type!

EpicSpawn is a powerful spawn plugin with first join, titles and broadcast messages.

MessagesAdvanced is the one plugin in which you have 99.9% total control over.

Re-SoupEx

Add the ability to hug other players on your server with HugMe!

Say bye to the badwords.

You control the chat! - Many chat management options!

A plugin that allows users to report things happening on the server.

A Simple Request Plugin

Server Broadcaster allows server owners to broadcast important messages or reminders across the server for all players to see.

A general usage/commands/fixes/chatmodes plugin

This Plugin edits the JoinMessage of Operators