Google Cloud Print iOS SDK by Conrad Kramer. It can integrates Google Cloud Print into Apple's AirPrint feature. This work uses AFIncrementalStore, AFOAuth2Client, and AFNetworking to communicate with the Cloud Print API, as mentioned by the author. Additional resources include prerequisites, how to build, and how to install.
In January, OnStar announced an API would allow third party developers to integrate their applications with OnStar's platform. Last week, General Motors announced its first partner for API integration: RelayRides. RelayRides is "[t]he world's largest peer to peer carsharing marketplace." The partnership with GM allows OnStar users to leave their keys in their cars when renting a car to a fellow RelayRider. The renter can then unlock the car with a smartphone app or by responding to a text message.
File Storage APIs have gone mainstream in the last year and developers are in a race to integrate the popular file storage options that are available to users on the internet. Dropbox has been one of the key players and, with the release of the Dropbox API aims to push the envelope by releasing not just support for newer features like sharing and search but also with the release of developer SDKs to maximize its reach across developers.