You will need node.js, mongodb and working gammu-smsd for this to work, example of our working gammu config can be found from example/ directory but you will need to change it depending on your gsm/3G modem and system.
Get a cheap laptop, install everything on it, install firefox, install r-kiosk, enable autologin and make firefox to start at boot. Now you have a self contained live shoutbox which you can just plugin to projector.
This project is licensed under the MIT license.