The feature is available on Google Maps for Mobile versions 4.4 and above on Android devices.
"Featuring your business location alongside your mobile ad is a powerful method to drive foot traffic and in store sales," says Google Mobile Ads Product Manager Surojit Chatterjee. "For instance, if a potential customer is looking for a wireless communications store like Sprint, an ad within GMM can display all Sprint locations near them. This not only delivers a relevant search experience, but also enables customers to visit the closest and most convenient Sprint store location.
When a user clicks a location, they’ll get more details about the business, like ad text, directions, click to call, and a link to the site.
As an advertiser, to use the feature, you must be a primary business owner and enable location extensions in Google Places. Campaigns must target iPhone and other "high-end" mobile devices with full mobile browsers. You’ll be charged when users click on the website URL or the phone icon.