Tango is a VoIP app and service that allows you to send free text messages, make free voice calls, and make free video calls to anyone around the world, provided of course they also use Tango. You can do this on your Wi-Fi, 3G or 4G connection. Tango works on Windows PC and on the iPhone, iPad, Android devices and Windows Phone. It has a simple interface, but the call and video quality have yet to be improved. Here are some tips and tricks to know more about Tango Text software.