where can I find a list of all the neighborhoods for all the US cities?

Downloadable database is preffered. Look: http://en.wikipedia.org/wiki/List_of_neighborhood_listings_by_city See the US section. When you select one of the US cities, you get a list of neighbourhoods for the city selected. This list is what I need for ALL cities, prefferably as a downloadable database. Such a database must be several times smaller than a zip codes databases (which are for sale on every crossroad in the web), so I don't think that this is something like an attempt to "download the internet". Any ideas on where can I buy such a neighbourhoods database?

Public Comments

1. The Homeland Stazi Agency The New FBI They have some.
2. http://www.city-data.com/