SwapKit is a unique protocol in that it allows developers to transcend the walls of the iPhone OS and pluck information from across a local network. In his own Mover application, Vulcano allows iPhone app users to add photos, videos or contacts to Mover's table. From here you can slide your various forms of media to nearby Mover app users. The result is a Bump-like application interface that allows for easy flow between devices. The Mover app will ship with SwapKit support in its next update. In this case, the application will use SwapKit's built-in UI to identify the sending and receiving app using a grand total of two lines of code.
SwapKit is available as a binary package or you can view the source repository in GitHub. The API documentation is also available on Vulcano's Infinite Labs site at infinite-labs.net/swapkit/docs/api.
Below is Erica Sadun's TUAW demo video of the protocol.