Just a suggestion, would it be possible to have member to member email that could be stored in the DB. This way when a user logs in, they can be notified of waiting mail, and even read it online. This would be a big plus for my users because a lot of them don't have an email address (or know what one is). Some of my forums are private and this would help to keep all correspondence on the server.
Hmm, why not try the Private messages Mod? It would do what you're asking. Your members could send a message to other members from the forum, and they can read it from the forum also. It's private, meaning only the person you send it to can read it. And it stored in the DB.