WhatsApp Messenger is a smartphone messaging app which allows you to exchange messages with your friends and contacts without having to pay for SMS. WhatsApp Messenger is cross platform and available for iPhone, BlackBerry, Android and Nokia (beta) and yes, those phones can all message each other! To send and receive messages, WhatsApp utilizes your existing smartphone internet data plan: 3G/EDGE (or Wi-Fi when available)

In addition to messaging, iPhone, Android and BlackBerry WhatsApp Messenger users can send each other unlimited images, video and audio media messages.