Soon after the launch of Amazon Fire TV, Koush, a well known developer has released his AllCast app to the new system. While before you had to sideload the app manually, now you can get it straight from the Amazon Appstore.
The app essentially allows users to pair their Android phone or tablet with Amazon Fire TV, allowing them to stream media content. Users can seamlessly switch between content source and input on your TV (Chromecast, Roku, Apple TV, etc.).