Pros and Cons of 5 Location APIs : Factual, Infochimps, Apigee, Hyperpublic, Foursquare
Nice run-through by StreetFight of some of the different Location APIs available to developers, including pricing options etc. I think that maybe IMMR might have one or two to add to the list (such as ESRI). Must check over there and see what they say.
