Google announced a new capability called App Indexing in late October that provides the ability for the search engine to index content found within Android Apps and display it on result pages.
Thanks to this app content indexing capability, mobile searchers will be able to click through to the exact location within an app where content is located. That means developers will be able to open up their previously siloed app-only content, increasing awareness of their brands (and content) and potentially, driving downloads too.
Developers/webmasters will be able to notify Google which content within an app they would like crawled and indexed by adding the rel=alternate elements within their XML sitemap or within the HTML of their Web pages. Google will soon roll out verification functionality within Webmaster Tools to support developers during implementation.
Google is only testing this functionality with a few Android developers, but if you've got an app (and content) you might want to consider expressing interest in the program now.