Ummm... what Suvro describes is an issue which I've written about elsewhere, in depth.
Many businesses offer services to a number of cities within their metro area, but frequently only have one physical address and phone numbers associated with it.
Google Maps doesn't handle this situation ideally -- they'll always offer consumers businesses which have physical footprint in the searched upon area, first, even though the other local providers may be better, lower-cost, or equally as valid.
While controversial, perhaps, it would be possible to contract for additional phone numbers for each of the cities that a business does business in, and to rent mailboxes in each of those locations in order to get street addresses there. This would allow more equal chances of ranking for all the localities where the business is offering services.
*** NOTE: this tactic should only be used for honest reasons -- that is, if you actually offer services within each of the cities for which you are setting up individual business listings. Also, Google frowns upon this tactic, even though they do not really have any other option available at this time. So, if you use this tactic, you should be aware that there may be some risk of penalization involved.
However, I believe that if a business is using the tactic for valid reasons to appear in SERPs for cities in which they are actually offering services, Google is unlikely to penalize them. For instance, if a tree cutting company offers their services throughout a major metro area, but do not have brick-and-mortar offices in the city, they ought to be able to appear for searches for that type of service in all the cities making up their major metro area.