That's probably the reason why Google added an OneBox for iPhone and Android apps. If you enter a query that includes keywords like 'download', 'application' or 'app' on an iPhone or on an Android phone, you'll see a list of results from Apple's App Store or from the Android Market. link
As of today, if you go to Google.com on your iPhone or Android-powered device and search for an app, we’ll show special links and content at the top of the search results.
You can tap these links to go directly to the app’s Android Market or iPhone App Store page. You can also get a quick look at some of the app’s basic details including the price, rating, and publisher. These results will appear when your search pertains to a mobile application and relevant, well-rated apps are found.
