Facebook has today announced the New Facebook messaging service. This brings texts, chats and emails together. With new Facebook messages you get faster interaction, integrated communication, better filtering, message forwarding, sending attachments and more features. Along this you get a [email protected] email address.
This features is not available to everyone as Facebook is slowly rolling out the feature to everyone. To get an invite you can apply for the invite via. facebook.com/about/messages. You can invite other people if you already have new facebook messages. If your friends already have New facebook message, you can request them as well.
You can know more about Facebook email via. Facebook help.