Users performing local business searches will often see an ad - delivered via Google's mainstay AdWords search ad platform - appear at the bottom of their phones. Google will get paid when users tap an ad to get more details, and when they tap to obtain directions or place a call.
With Maps actively used on hundreds of millions of Android/iOS phones and tablets - Google claims to have 1B+ monthly PC/mobile Maps users - the new ad format should have tremendous reach. It should also make Google a bigger rival to YELP for the ad dollars of local businesses.
The ads will follow the arrival of Google's well-received iPhone and iPad Maps apps, and the summer intro of an across-the-board overhaul for the Maps apps that includes a cleaner UI, more Zagat content, and better navigation/traffic tools. Waze integration will come soon, FTC willing.