That headline may be a trifle misleading. Not intentional, of course - but we do need to clear a few things up.
This isn't Windows Phone 7 Tango in action here. This is the Windows Phone 7 Tango app. Confused? You needn't be.
Tango is purportedly the next big Windows Phone 7 update to come after Mango. But that isn't what Aaron Woodman, from the Windows Phone team is showing off here.
He's showing off the Tango app (Tango is a mobile video company) on the HTC Titan - the first time we've seen video calling on Microsoft's mobile OS.
It looks slick and very FaceTime-like with the switching between the two cameras.
But we're still a bit baffled as to why Microsoft hasn't put a native video calling option into Mango though, especially as the handsets for the updated OS (such as the Titan and the HTC Radar) are packing front facing cams.