If Apple doesn’t make it possible for iMessages to work on non-iOS clients, it’s likely to be about as successful as MobileMe or Ping
As one of the core new features highlighted today in iOS 5, iMessages has one purpose: to kill SMS. That is, traditional carrier-controlled text messages. iMessages will do this by replacing SMS with a service that Apple is in control of across all of their iOS devices. And here’s the real death blow: iMessages will be completely free.