Windows 8 is the star at the Microsoft Build event going on right now, but you don't have to be there to get your hands on this next version of the operating system.
Microsoft will be releasing a Developer Preview for download later tonight. Windows president writes in a blog post:
You probably want to try out the preview release—and you can. Starting later tonight you can download the Windows 8 Developer Preview. This includes a 64-bit (x64) build with development tools to build apps, and a 32-bit (x86) or 64-bit (x64) build without development tools. 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.
Upgrade from Windows 7 installation is not supported for pre-release code; only clean installs are supported. Reminder: this is a developer preview release and is not meant for production. It is not a beta release. We will be updating the release with various quality updates and drivers over the coming weeks/months just to exercise our overall update and telemetry mechanisms.
Stay tuned for more on Windows 8.