Went to https://dev.windows.com/en-US/iot and found that you can download a Windows10 preview for the PI as of 4/29/15.
You will need a PC running Windows 10 technical preview to even get the OS on the SD card.
It takes a long time for the PI to boot the first time. I mean like 10 minutes.
After that it boots headless and you use PowerShell to remote into the PI. Have not done much else with it yet because I had to install windows 10 on a space PC etc... However the getting started gives instructions for downloading Visual Studio 2015 and programming the PI.