BlackBerry Messenger is on the way for iOS and Android. We haven’t seen them yet, but they should arrive soon. Especially now that the user guide has leaked. We’re sure the guide will come along to an official capacity soon, and the apps should be soon after.
The guide explains how the app works. It goes over the basic features and functionality. Right now there is now release date, but BlackBerry did say that BBM for iOS and Android should release before September. August is almost over.
You can check out the guide here.