Google announced a new feature this week that lists apps in mobile search results. When searching for an app by name from your iPhone (it works with Android too, naturally), the top result is a link to the app's home in the App Store. In addition to the link, you get information like rating, publisher and price.
That's the idea, at least. I got limited results in my own testing. "Shazam Download" produced the expected result, but searching for Twitterrific didn't. I tried adding "download," "app," "iPhone," and other qualifiers to no avail. Likewise, searching "Bank of America App" worked, but variations on "Gowalla" did not. Google notes that "The mobile app results will only be returned when relevant, well-rated apps are found," but who knows what that actually means.
This feature is limited to the USA for now, but Google promises that it's in the works for other countries.