Microsoft has released the Windows 10 developer tools that will help programmers build applications that take advantage of the platforms new features like Cortana and Action center



From Neowin:

The SDK, which you can find at the source links below, is the first release for developers and expect the tools to be updated as the OS progresses towards RTM this summer. If you want to download and use the bits, Microsoft says to follow these steps:

Sign up for the Windows Insider Program, if you haven't already.
Install, or upgrade to, the latest flight of Windows 10 Technical Preview to best support Windows Universal App Platform development.
Run Windows Update to check for the latest updates.
If you're running CTP5 or earlier, uninstall your previous version of Visual Studio 2015.
Install the tools; both Visual Studio 2015 CTP6 and the Tools for Windows 10 Technical Preview, which includes the SDK, are required when developing for the Windows Universal App Platform. (To install the .iso file, download the files, right-click the local copy, and then select Mount.)

  Microsoft has released the Windows 10 Technical Preview tools for developers