Windows 8 Developer Preview is Available for Download

Microsoft has recently announced the Windows 8 Developer Preview in the BUILD conference, and the download is now free and open to the general public. No registration is required.

http://msdn.microsoft.com/en-us/windows/apps/br229516

If you are interested in installing it on a virtual machine, your best bet is Virtual Box from Oracle. One of my colleagues tried it on VMWare, and it did not work at all. Let us know what your experience is with this build.