Windows 10 for IOT is available here. It actually works with Raspberry Pi 2, MinnowBoard Max, Intel Galileo , Windows Remote Arduino and Windows Virtual Shields for Arduino.
You must be a member of Microsoft Connect or sign up for the Connect Program. Also, if your friends want to work with you then they have to do the whole work flow to get their one copy of the software. In addition, it only works if you have a Windows 10 machine with the most recent build, post 10069, which is why you need to be signed up with the Windows Insider program.
Here are a few words about the suported hardware.
The Raspberry Pi 2 is a low cost ($35), credit-card sized computer that plugs into a computer monitor or TV, and uses a standard keyboard and mouse. The Raspberry Pi 2 runs Windows 10 IoT Core.
MinnowBoard MAX ($99) is an open hardware embedded board with the Intel Atom E38XX series SOC at its core. MinnowBoard MAX supports Windows 10 IoT Core Insider Preview.
Intel Galileo ($65)is the first in a line of Arduino-certified development boards based on Intel x86 architecture and is designed for the maker and education communities. Galileo supports only the previous versions of Windows, not Windows 10 IoT Core.
Windows Virtual Shields for Arduino is an open-source library primarily for the Arduino UNO which communicates with an open-source Universal Windows application running on all Windows 10 devices, including Windows Lumia phones. The library exposes Lumia phones' sensors and capabilities to the an Arduino Wiring Sketch.