Bukkit

/channel or /ch
/channel <arg> :

create <channel> Create a channel

leave <channel> Leave a channel

join <channel> join a channel

disband <channel> disband a channel thats you are an admin

list List every channels

invite <player> <channel> invite a player in a channel thats you are in

kick <player> <channel> kick a user(can't kick an admin) of a channel

/staffchat or /sc
allow you to talk in the staff chat via : /sc <message>

/switchchat or /ss
switch if you want to receive a message or not (actually it inly work with the Staff Chat)

/chat or /c[edit]
/c <channel> <message> see with /ch list the channels in colors where you can speak

/broadcast <message> or /bd
broadcast a message to the server

/clearchat [<player>] or /cc
clear the global or the plkayer chat