WhatsAPP for windows
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.