KIK Messenger is a free mobile app that will enable real time texting with friends. The app is available for Blackberry, iPhone, iPod and Android Phones. It has a clean and simple interface with no advertisements.
KIK Messenger tells you when a message has been sent, delivered, read and even when someone is typing back, turning regular texting into real-time conversations.
This video gives a small demo on KIK Messenger.