Well known developer, Koushik Dutta, has released his AirCast app.
Koush reverse engineered the Chromecast protocols to create his AirCast app. Right now the app will (supposedly) only work for 2 days; it’s for testing and suggestions only. Also, you’ll have to sideload the app, so make sure you know how to install this app outside of Google Play.
AirCast works well, allowing you to cast videos from Dropbox, Google Drive, and your Android gallery. Picture casting isn’t supported, though I was able to get a picture to show up on a black screen.
AirCast shows what’s possible with Chromecast, making the Chromecast dongle even more powerful.