Silvery - 10:20 pm on Jun 10, 2010 (gmt 0)

It sounds very much like you're some sort of a national retailer site of some sort.

If you don't have a physical presence in each of those cities, you'd better not attempt to expand out via Google Maps as you're planning, because this would run against their policies.

If you do have a store or people physically working in each city, you could use either the subdomain or a subdirectory that is unique to your site.