Today, Google announced a new capability of Google Search, called app indexing, that uses the expertise of webmasters to help create a seamless user experience across websites and mobile apps.
Just like it crawls and indexes websites, Googlebot can now index content in your Android app. Webmasters will be able to indicate which app content you'd like Google to index in the same way you do for webpages today — through your existing Sitemap file and through Webmaster Tools. If both the webpage and the app contents are successfully indexed, Google will then try to show deep links to your app straight in our search results when we think they’re relevant for the user’s query and if the user has the app installed. When users tap on these deep links, your app will launch and take them directly to the content they need.
Here’s an example of a search for home listings in Mountain View:
For more details on implementation and for information on how to sign up, visit Google's developer site.