I'm giving a brief presentation for my local Google Developer's Group next week, and this is a collection of the information I've gathered for the presentation.
Apps available now:
Netflix (Android and iOS)
YouTube (Android, iOS and web)
Google Play Music (Android) [Oddly, this doesn't work from the web.]
Google Play Movies (Android, Web)
Broadcast a tab from Chrome (still a beta)
XBMC is starting to have working solutions, but at this point they are hacks.
Apps that are believed to be in progress:
Pocket Casts [a podcast app for Android]
Redbox Instant by Verizon
Additionally there is Lima a Kickstart project that looks like a simplified, hardware dongle for local media:
Lima Announces Support for Google Chromecast
This article is a great description of why a Chromecast is desirable:
How Chromecast fundamentally changed how my family watches TV - Lost Remote
This might be interesting to those that have an Android TV stick laying around.
CheapCast, the Chromecast emulator, is now in the Play Store
It is widely believed that the Chromecast succeeded far beyond Google's initial expectations.
Google’s Chromecast team rapidly expanding after explosive launch
The Chromecast SDK is still a Developer Preview, we will not see new Chromecast apps until the SDK is fully released. [One is explicitly forbidden to release with the preview version of the SDK.]
You may have heard about Google blocking the "AllCast" app... well the developer had no business doing what he was doing. He was coding around the SDK and the SDK isn't even released yet. They didn't so much "block" his app as they closed an unintended hole. It is likely that local streaming will become available again:
Google responds to claims they intentionally blocked AllCast
Here's a link to the Chrome tutorial for using Chromecast
It is very simple to do. Android and iOS work similarly, with the usual extra Java / Objective C pain.
Device discovery uses a new open protocol from Netflix and YouTube: