All messages are sent instantly.
If you mean something more like a live chat, it's called IRC.
I believe Monty was suggesting something akin to a chatroom per region. It's not a bad idea, as it is in between letters and using IRC, though either letters or IRC would serve better if you wanted permanence or instant feedback.
The advantage you may be thinking of is that it would be instant notification, but the reality is you would simply type a message, and then no one would respond for quite a while and you might as well have sent a letter.
