We are currently testing and polishing the next iPhone version with a new messenger for one to one messaging.
In the new version you'll see Messages instead of Inbox and your conversations are grouped per avatar, latest ones on top. Message views look a lot like chatting in virtual places and also work similarly. Instead of replying to a message you just "Say" something and your message is delivered to the recipient. And you'll see the whole history of your conversation. It works nicely with Push Notifications too.
29th April
