Google Places is free web based service by Google where business owners can create their business listings alongside publishing all important and useful information for their customers.
Business owner can provide all important and useful information ranging from company name to contact numbers to their physical location on map. Not only this, you can add business timings, photos, videos and much more. Furthermore you can also create customized vouchers/coupons to attract more customers.
Business information once submitted to Google Places is then available from all of Google publically accessible services e.g. Google Earth, search, maps etc. Also visible from Google Maps iPhone application.
For a detailed and interactive idea on how Places work and help your business grow, please watch the following video.