Is there a standard database of records mapping city/state/zip to lat/lng? I found this database, and the USPS has a simple (no lat/lng) API, but is there another recommended alternative?
Update: Found this too: http://www.geopostcodes.com/
Just a small note. Most of these 3rd party city/state/zip to lat/lng databases are based on the US Census Tiger data. Start with the Census 2000, the zip code data was replaced with ZCTA - which is an approximation of zipcodes. Here's an explanation from the Census site (from 2011):
ZIP Code Tabulation Areas (ZCTAs™) are a new statistical entity developed by the U.S. Census Bureau for tabulating summary statistics from Census 2000. This new entity was developed to overcome the difficulties in precisely defining the land area covered by each ZIP Code®. Defining the extent of an area is necessary in order to accurately tabulate census data for that area.
ZCTAs are generalized area representations of U.S. Postal Service (USPS) ZIP Code service areas. Simply put, each one is built by aggregating the Census 2000 blocks, whose addresses use a given ZIP Code, into a ZCTA which gets that ZIP Code assigned as its ZCTA code. They represent the majority USPS five-digit ZIP Code found in a given area. For those areas where it is difficult to determine the prevailing five-digit ZIP Code, the higher-level three-digit ZIP Code is used for the ZCTA code. For more information, please refer to the ZCTA (FAQ) Frequently Asked Questions Web page.
The link below is an updated explanation (2013):
http://www.census.gov/geo/reference/zctas.html
The OpenGeoCode.Org team
ADDED 12/17/13: Our (FREE) state/city/zip dataset (CSV) can be found at the link below. It is derived from public domain "government" datasets: