As a business owner, you should respond to reviews about your business when you are given the chance. Google recently enabled the ability for owners to publicly respond to reviews from customers on their Google Places page. This is yet another reason to claim your Google Places listing in Google. Other directory sites like Yelp have had this capability for over a year; same for SuperPages, CitySearch, and TripAdvisor to name just a few. Both Google and Yelp give you some good suggestions and guidelines on how to respond appropriately to reviews. The short summary is: be nice and view each review as an opportunity to improve your business.
You must have your business claimed via Google Places to respond to reviews. Simply login to your Google Places account or go directly to your listing on Google Maps while logged into your Google account in which your Google Places listing is stored against.
The rest is pretty self-explanatory. But remember be nice and view each review as an opportunity to improve your business as “The entire world will be able to read it.”
UPDATE 8/26/2010:
As of today Google is no longer showing Yelp reviews within Google Places.