Geocoding - the should I use API or database?

I need my users to be able t开发者_开发技巧o regularly geocode their addresses, but NOT onto a map - I simply need to be able to translate an address into a set of lat/long coordinates so my site can react accordingly.

It seems like Google doesn't want you to use their geocoding service unless you are actually plotting on a map. On the other hand, I want to make sure that the service is reliable and will last a long time.

I'd also consider downloading some kind of address database and running the requests myself if I knew where to find it.

Any ideas?

A good alternative to the Google Geocoding API is SimpleGeo (no affiliation). They are more liberal when it comes to the Terms of Service, meaning you have fewer restrictions of what you can do with the data.

On the other hand, I remember a quote from their founder saying their non-US data is not on the same level (or better) than, for example, the data from Google.

Note this answer is incorrect, but retained for posterity.

If you are under 2,500 requests per day, you should be fine using Google's geocoding API: http://code.google.com/apis/maps/documentation/geocoding/

Are you basing your assumption about what Google wants on this?

This document is intended for website and mobile developers who want to use geocoding data within maps provided by one of the Google Maps APIs. It provides an introduction to using this API and reference material on the available parameters.

That's describing the audience of the document, not the audience of the API itself.