To use this app, you obviously need a PlayStation Network account. If you have one, just log in to access all your PSN contacts and start a conversation with any of them, or even create a new group.
One of the most interesting features in PlayStation Messages is that it lets you use dozens of custom emoji and stickers from the most popular PlayStation games. For instance, there's a sticker of Nathan Drake, from Uncharted, that says everything you could want to say to a friend.
PlayStation Messages is an interesting IM client that will undoubtedly appeal to anyone who frequently games on PlayStation 3 or 4.
Requires Android 4.0.3 or higher