Kik Messenger for Android is a free-to-use, cross-platform messaging service. The application allows users to easily and quickly communicate over a mobile data connection with no charge for text messages.
I feel this application's main feature that puts it up against Apple's iMessage and Blackberry Messenger is the attractive UI. It is very well designed and has a polished, minimal feel to it.
The developers at Kik say this about their application:
Kik Messenger is the totally free, crazy-fast cross-platform messenger app that connects you to your friends in real-time. Use Kik to chat, share pictures privately, plan outings with groups, and stay connected to the people who matter most to you.
You’re going to fall in love with Kik Messenger.