Geocoding involves converting a description of a physical address into coordinates that represent that location on a map to perform spatial analysis. This tutorial on the Google Maps APIs blog describes the two approaches to geocoding with Google Maps APIs, and when to use them.
NASA has released a new API (the EPIC API) which provides programmatic access to images pulled from the EPIC camera. EPIC sits upon the DSCOVR satellite and constantly provides images from the Earth's sunlit side. Developers can retrieve images from the camera along with associated metadata.
Quova's is a geolocation service, went free last November. The company has revamped its developer portal and added a few awesome new features to the Quova API. The company also added JSON as a response format, as so many other APIs have lately. Unlike the APIs ditching XML, Quova is keeping the XML format and expanding developer options. Also, the company added a developer forum and app gallery to its portal, to encourage community around its API.