I saw this yesterday from Fierce Wireless http://www.fiercewireless.com/story/sprint-goes-ott-messaging-plus-app-jibe/2013-10-14
being talked about so I decided to give it a spin. I have to say it works pretty good, including doing video calls on 3G. It is for IOS and Android, so give it a spin, and yes you can do regular sms/mms thru the app to for those others who do not have it installed.