Ramblings from another nerd on the grid
“You probably want to try out the preview release—and you can. Starting at 8PM today, Seattle time, you can download all of the code that attendees at BUILD received. This includes 32 or 64 bit x86 builds, with or without development tools. The releases also include a suite of sample/SDK applications and the SDK (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. You download with a Windows Live ID (which you might want to use to test out some of the new roaming features).”
See the full post at http://blogs.msdn.com/b/b8/archive/2011/09/13/welcome-to-windows-8-the-developer-preview.aspx.
I think they clarified the statement saying that the download does not require a Windows Live ID, but that you would not be able to experience full functionality with roaming profiles if you did not have one.
Scott Hanselman has a wonderful posting on how to install the Windows 8 Developer Preview on an existing Windows 7 base workstation as a boot-to-VHD. Tried it this morning and worked wonderfully. See www.hanselman.com/.../GuideToInstallingAndBootingWindows8DeveloperPreviewOffAVHDVirtualHardDisk.aspx