We've covered Factual a number of times, most recently asking if it will become the go-to location database. Now the company has expanded its offering with improved datasets, new datasets and a new iPhone SDK. Its local data now covers 27 countries and contains more than 30 million individual business listings.
Wikimapia is a web service that allows users to edit information on a world map in a wiki format. Users of the site can add places, edit them, and get the information previous users have entered. The info there is currently pretty sparse, but the service is rather new. The company also recently released a Wikimapia API that supports getting information from the web service.