FireChat enables iPhones to leverage iOS 7's Apple Multipeer Connectivity framework to link directly via Bluetooth personal area networks (PANs), peer-to-peer Wi-Fi or a traditional Wi-Fi network, obviating the need for access to a cellular network. OpenGarden's website indicates the company is working on a Google (NASDAQ:GOOG) Android version of FireChat as well.
http://www.fiercewireless.com/tech/story/apples-ios-7-taking-cellular-out-networking/2014-03-30