The Mobage iOS SDK by DeNA allows API communication to implement mobile gaming functionalities. To start development, users can create a project in XCode, import & integrate the SDK, and enable login. Additional resources include social capabilities, working with the People API.
Magickly aims to make image manipulation possible as a simple web service. The Magickly API is very easy to use, and completely open source. It requires no API key, and allows a developer to use a lot of different image manipulations on any web-accessible image. Magickly is an open source, simplified version of the Aviary Effects API, which has a contest ending next week.
Aviary, the photo editing suite that includes a number of Aviary APIs to incorporate photo editing into your web applications is moving its tools to mobile. Today it announced SDKs for iPhone and Android, as well as an impressively long list of launch partners who have already incorporated the platform in their mobile apps.