So how can you get your business on the map? In addition to Local Business Ad (LBA), Googel with new AdWords interface and AdWords API v2009, have a much simpler solution available “Location Extensions,” that allow you to add location information to any text ad in your campaigns. Extending your ads with location information will enable them to be shown on Google.com and other properties (such as Google Maps), bringing you closer to your customers' local searches. For e.g., Say your business has a few branches open throughout the city, and you want to add location information to your existing ads. The first step is to retrieve location of each branch, using GeoLocationService, which uses a process known as "geocoding." Next step's to use CampaignAdExtensionService to add a location extension to your campaign using information returned by GeoLocationService.
More info: AdWords API blog