I just downloaded WhatsApp Messenger on my BlackBerry.
It is a Smartphone Messenger which replaces SMS. This app even lets me send pictures, video and other multi-media!
WhatsApp Messenger is available for BlackBerry, iPhone, Android and Nokia and there is no PIN or username to remember – it works just like SMS and uses your internet data plan.
Get it now from http://www.whatsapp.com/download/ and say good-bye to SMS.