Reverse geocoding services

I'm working on a project that returns information based on the user's location. I also want to display the user's town in text (no map) so they can change it if it's not accurate.

If things go well I hope this will be more than a small experiment, so can anyone recommend a good reverse geocoding service with the least restrictions? I notice that Google/Yahoo have a limit to the number of daily queries along with other usage terms. I basically need to take latitude and longitude and convert them to a city/town (which I presume cannot be done using the HTML5 Geolocation API).

Geocoda just launched a geocoding and spatial database service and offers up to 1K queries a month free, with paid plans starting at $49 for 25,000 queries/month. SimpleGeo just closed their Context API so you may want to look at Geocoda or other alternatives.

You're correct, the browser geolocation API only provides coordinates.

I use SimpleGeo a lot and recommend them. They offer 10K queries a day free then 0.25USD per 1K calls after that. Their Context API is what you're going to want, it pretty much does what is says on the tin. Works server-side and client-side (without requiring you to draw a map, like Google.)

GeoNames can also do this and allows up to 30K "credits" a day, different queries expend different credit amounts. The free service has highly variable performance, the paid service is more consistent. I've used them in the past, but don't much anymore because of the difficulty of automatically dealing with their data, which is more "pure" but less meaningful to most people.