Free Texting in Europe: Get Whats App for your smart phone: WHEU Chaperones will have Whats App on their phones to communicate with students and parents

How it works

WhatsApp Messenger is a cross-platform mobile messaging app which allows you to exchange messages without having to pay for SMS. WhatsApp Messenger is available for iPhone, BlackBerry, Android, Windows Phone and Nokia and yes, those phones can all message each other! Because WhatsApp Messenger uses the same internet data plan that you use for email and web browsing, there is no cost to message and stay in touch with your friends.
In addition to basic messaging WhatsApp users can create groups, send each other unlimited images, video and audio media messages.

http://www.whatsapp.com/download/