Ver 1.1, for wp7

WhatsApp Messenger is a cross-platform mobile messenger that replaces SMS and works through the existing internet data plan of your device. WhatsApp is available for Windows Phone, iPhone, BlackBerry, Android and Nokia Symbian60 phones. 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.