Since the //Build/ conference is a technical preview of Windows 10 for Raspberry PI 2 is available. With that the promise of Microsoft (Windows on all devices) becomes reality.
There will be 3 versions of Windows 10 IoT available: For Industry Devices, Mobile Devices and Core. Installing Windows 10 IoT Core on a Raspberry PI 2 very easy.
More information on http://windowsondevices.com and demos http://ms-iot.github.io/content/win10/StartCoding.htm.
While installing you will see these screens pass by. The first startup of Windows 10 IoT Core takes a bit longer, some additional setups are being done. No worries next time the startup is fairly fast.
When finished you see this.
In this early version some functions are not ready yet, but that will change soon.
On a Windows 10 machine with Visual Studio 2015 you can make a ‘normal’ Windows Universal App. This app can be deployed to your Raspberry PI 2 and the standard debug/F5 experience will just work.
In the IoT makers world a lot of components are available and most will work on the Raspberry PI 2 with Windows 10 IoT Core too. Have a look at the examples on http://windowsondevices.com.
I have ordered some components and soon I will post more on these experiments. This is fun 
!