Hi,
I've just released airnef, a free, open-source utility for wireless image/video transfers from WiFi-equipped Nikon bodies. It's coded in Python and runs on Windows/OSX/Linux - I've included both pre-built executables/installers and full source for those who want to tinker in the Python interpreter. The PTP-IP logic is based on Joe FitzPatrick's excellent WiFi reverse-engineering work (https://nikonhacker.com/wiki/WU-1a).
Here is a link to airnef's home page, which has download links and a user guide:
http://testcams.com/airnef/
And here's a YouTube demo of airnef in action: