Revel Systems API makes it possible to run a cash register, a restaurant and a mobile point-of-sale system with an iPad as the center of the user interface. Check out what Revel has to say about the API on their website.
Twelve APIs have been added to the ProgrammableWeb directory in categories including Finance, Location, Security and Education. Featured today the Voysis API that gives voice-enabled applications natural language instruction and brand search and discovery abilities. Here's a rundown of what is new.