A couple days ago, Google's Shawn Simister released code via GitHub showing how Android developers can integrate Google Now Actions directly into their Android apps.
Essentially, Google Now Actions let you add a voice search string intent identifier that will trigger Google Now to bring up a search result set, not in Google search, but rather your app. So if you wanted to search for movies nearby, you may be able to say "show me movies in the next two hours" and it might bring up a search result set within the Fandango app, if they integrated Google Now Actions.
Here is a video from Jarek Wilkiewicz that explains it in greater detail:
Forum discussion at Google+.
