I have added a module for sending private messages. You should see a link by the log out link for messages. It is set-up that you will receive an email when someone sends you a private message. If you don't want to receive any emails or don't want to be private messaged you can opt out by going to your account, selecting edit and you will have a section called Private Messages, there you can untick Enable private messages and Receive email notification for incoming private messages.
