So... I was thinking... 
Apple introduced FaceTime with iPhone 4 and iOS 4. FaceTime then moved on to the other iOS devices, first the iPod touch 4G, and then the iPad 2. Those devices had their own FaceTime apps.
Now, Apple introduced iMessages in the Messages app in iOS 5. iMessages is going to be available to all iOS devices adding a Messages app to the iPads and iPods.
Both iMessages and FaceTime made so that people could contact each other for free between two iOS devices. But to make calls, you still have to rely on the carriers.
My point is... If the Messages app can send iMessages for free, why can't they do so that the Phone app can make "iCalls" for free?
Apple introduced FaceTime with iPhone 4 and iOS 4. FaceTime then moved on to the other iOS devices, first the iPod touch 4G, and then the iPad 2. Those devices had their own FaceTime apps.
Now, Apple introduced iMessages in the Messages app in iOS 5. iMessages is going to be available to all iOS devices adding a Messages app to the iPads and iPods.
Both iMessages and FaceTime made so that people could contact each other for free between two iOS devices. But to make calls, you still have to rely on the carriers.
My point is... If the Messages app can send iMessages for free, why can't they do so that the Phone app can make "iCalls" for free?