Hey, AT&T subscribers: you no longer need an iPhone to make calls over WiFi. The carrier has introduced WiFi calling for Android. If you have a supporting device (currently limited to the LG G4), a postpaid plan and HD Voice support, you can grab an update that lets you make calls over the internet when cell service just isn't an option. As on the iPhone, what you pay for a call only depends on who you're calling -- you can reach a US number at no extra charge while you're abroad. AT&T certainly isn't the first out of the gate with WiFi calling on Android, but this will definitely make a difference if you'd rather not switch networks just to get the improved coverage.