As of today, if you’re a verified Google Places business owner, you can respond to customer reviews.
From the Google Lat Long Blog:
Engaging with the people who have shared their thoughts about your business is a great way to get to know your customers and find out more. By responding, you can build stronger relationships with existing and prospective customers.
So now it appears that Google is not only giving Yelp, but also Get Satisfaction, a run for its money. Make sure to check out the new Places features in Google Maps for Mobile.