CodeCanyon - Private Messages for UserPro v4.4 - 7124805
Messaging is a cool add-on, it moves your UserPro powered site to another level by letting people interact with each other, awesome new message notifications and easily initiate chats and reply to messages.
This plugin adds private messaging between users and allows users to receive notifications about new messages, view conversations, reply to other users, It includes nice features such as emoticons, nice ajax notifications, easy conversations and quick-reply.