One of the new features with iOS 5 is Apple’s iMessage service. First unveiled in June, iMessage works through the existing Message app, delivering real-time messages that can include photos and videos. The only requirement is that the other person must also be using an iDevice with iOS 5 installed.

Unlike SMS, iMessages are free and unlimited. As such, each message transmits over a carrier’s data networks and the Internet, much like e-mail, and not through cellular networks.

Best of all, iMessage is seemless. On iDevices with iOS 5, iMessage is automatically turned on via the Settings app under Messages; you can also turn off the feature here too. On the iPhone, any message that cannot be sent via iMessage is automatically sent using a carrier’s existing SMS service.

iMessage Setup - iPhone

iMessage Setup - iPhone

How do you tell if you’re using iMessage as opposed to SMS? It’s simple, really. Within the Message app, green bubbles represent SMS messages (get it, green=money), while blue bubbles use iMessage. These colors are indicated as soon as you type in a user’s email address or cell phone number. Plus, if the user isn’t registered with iMessage (in other words, they aren’t using iOS 5), his or her name turns red.

 

Person Isn't iMessage User (RED)

Person Isn't iMessage User (RED)

Message Sent Via iMessage

Message Sent Via iMessage

Finally, iMessage will indicate whether your message was delivered successfully or not.