I have a development kit for Leap Motion that arrived last week and I've been working on an Objective-C/C++ wrapper for the C++ Leap Motion SDK. I used opaque pointers to contain the Objective-C/C++ code into one file so that the header can be included in vanilla Objective-C apps. Now that I have a starting point I'm working with the data from Leap Motion. My first goal is to make a functional mouse counterpart that can be used "hands free." Here's a video of my of basic mouse control. I use the position and direction of the finger to cast a ray into the monitor (ray tracing anyone?). Using the intersection point and a lot of math you can start to translate the raw leap data into something meaningful for an application.
Going further I'm investigating the best way to recognize a tap gesture and what that will look like in practice.