It supports YouTube, Chrome browser tab mirroring, Google Play Music, Google Play Movies, and screen mirroring. Most 3rd party apps using Google Cast SDK should also work. Yes, it works on Amazon FireTV boxes and sticks, and other major brands of Android TV boxes.
This is the trial apk, which has full features, except this current apk will expire on Feb 29, 2016, so hurry up !
http://www.youmap.com/YouMapCastReceiver.apk [apk updated on Feb-02-2015, version 1.4.0]