This week's book giveaways are in the Refactoring and Agile forums. We're giving away four copies each of Re-engineering Legacy Software and Docker in Action and have the authors on-line! See this thread and this one for details.
The first thing I'd recommend is to develop it initially against dumbster or something simmilar. That way you can find your feet with JavaMail without having to understand all the possible network and configuration issues you can get connecting to a remote SMTP server.