Hello, I have an iPhone running iOS 6.1.4; I am using iMessage in America, iMessaging back and forth with a friend who is currently overseas. I turned off MMS / SMS so that charges won't occur if iMessage fails at a certain point. My provider is AT&T and I am using 4G LTE with Unlimited Messaging. My question is: Being on 4G LTE does it cost me at all for iMessaging someone who is overseas? Or do I need to be on Wi-Fi for it to be free... Or is it free regardless? Thanks!