From: http://blog.searchenginewatch.com/blog/051211-213738

One of those SearchDay stories was titled: A Hearty Buffet of Look-Up Databases, and looked at the many and free online databases that Melissa Data made available. Melissa Data is a mailing company and offers these online tools as a public service. Everything from “Zip Codes within a certain radius” to Income Tax stats to “area codes within a certain radius.” Most of the databases listed in my 2003 article are still available.

Ok, so after looking at that overview (an invite to do so) you’ll be happy to know that Melissa Data continues to offer free lookup databases. In fact, when I wrote the article in 2003, 18 databases were listed.

It’s almost 2006 and that “hearty buffet” of databases, has grown even larger, now home to more than 30 databases and tools. Here are links to some of the latest offerings. Google Maps mashup folks will be happy to learn that several of these new databases utilize Google Maps.

+ ZIP Code Maps
“Displays a map with the boundary of a 5-digit ZIP Code”
Uses Google Maps

+ City Maps
“Displays a city or town boundary map and demographics.”
Uses Google Maps

+ Congress Maps
“Maps of a congressional districts and information about representative.”
Uses Google Maps

+ Home Sales
“Get the monthly home sales and selling price by ZIP Code.”
See Also: HomePages.com

+ County Maps
“Displays a county boundary map.”
Uses Google Maps

+ School District Maps
“Displays public school district boundary maps nationwide.”
Uses Google Maps

Melissa Data is a fantastic one-stop shop for this ready reference type of data. A user gets 500 lookups per day for free. It’s possible to get more by subscribing to one of two plans.