Steven Sinofsky has announced that tonight at 8PM PDT Microsoft will release a developers preview of Windows 8. I can imagine that the response will be great, so download speeds may not be the best. But, I can assure you I will be downloading it starting at 8:00:01 PDT, along with many others. I can’t wait to give it a whirl!
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.