Facebook Messenger for BlackBerry allows you to keep in touch with your friends on Facebook very easily through your phone.
Open up the Facebook Messenger app and you'll be able to see your Facebook message history, tapping on a message to open it and reply, or creating a new message. Any message you send from Facebook Messenger is automatically saved to Facebook, as if you'd sent it from your PC or the Facebook app.
The great thing about Facebook Messenger is that it supports SMS. You can browse through the list of your contacts and quickly view if they are reachable by Facebook or by SMS too. Select a contact with a phone icon next to their name and Facebook Messenger will give you the option to call that person, send them an SMS, or message them via Facebook.
Other neat features of Facebook Messenger include the ability to have group conversations, and to add photos to chats. There are some built-in privacy safeguards too, such as message history being cleared when you add someone else to a one-on-one conversation.
One of the few criticisms you could level at Facebook Messenger is that it doesn't actually show you which of your contacts are currently online, as you can with the original Facebook app.
Still, Facebook Messenger offers a fast and easy way to send text messages to your Facebook contacts.