On Tuesday Facebook launched a new app for smartphones , allowing users to send text messages to each other from their smartphones using Facebook’s messaging system.
Facebook’s Messenger app is also capable of group texting, letting you pick multiple Facebook contacts and send them all texts at once. If a FB user is logged into the new message app, it’ll show up there. If not, they get the message sent to them as an SMS, so long as they’ve registered their phone with Facebook. The service is mobile-focused, so it doesn’t completely integrate with Facebook Messages, which tries to route a message to a person using whatever channel Facebook thinks is most likely for you to get it fastest.
The app is already available for Android and Blackberry phones along with the iPhone, iPod Touch, and iPad (although the app is not yet optimized for the iPad's larger screen.)