Good news to all Windows enthusiasts who have been eagerly waiting for the official Windows 8 build. You will be able to download an official build of Windows 8 right from Microsoft very soon. Yes, starting from tonight (14/9/2011, 03:00 GMT) you will be able download the Windows 8 Developer Preview.
The Windows 8 Developer Preview will be available in both x86 and x64 builds. The releases also include a suite of sample applications (please note these are merely illustrations of potential apps, not apps that we intend to ship with Windows 8). The ISOs are linked to from http://dev.windows.com.
Please note that upgrade from Windows 7 installation is not supported for pre-release code; only clean installs are supported.
You needn’t to activate Windows 8 Developer Preview. Simply download, install, and start using the next generation Windows 8.
UPDATE: Windows 8 Developer Preview is now available to download from the link given below. The Developer Preview is available in three flavors:
Windows Developer Preview with developer tools (x64)
Windows Developer Preview English (x64)
Windows Developer Preview English (x86)