Just upgraded to WeChat 4.0 for Windows Phone 8 and can now see that they've added HD Video chat option. Check it out, no need to wait for viber or tango and these other apps!
WeChat | Windows Phone Apps+Games Store (United Kingdom) (UK)
WeChat | Windows Phone Apps+Games Store (United Kingdom) (US)
Or just search WeChat in the app store.
WeChat | Windows Phone Apps+Games Store (United Kingdom) (UK)
WeChat | Windows Phone Apps+Games Store (United Kingdom) (US)
Or just search WeChat in the app store.