The SkypeKit SDK supplies APIs for plugging into Skype's messaging, voice, and video chat service. It also includes an implementation of SILK, the company's audio compression codec. The SDK is currently in closed beta and is only supported on Linux at this stage. Skype intends to extend the SDK to additional platforms next month and will eventually make it more broadly accessible. Skype envisions hardware makers using the SDK to add voice and video chat to devices like televisions.
See also Ars Technica and Engadget.