Windows 8 Consumer Preview is prerelease software that may be substantially modified before it’s commercially released. Microsoft makes no warranties, express or implied, with respect to the information provided here. Some product features and functionality may require additional hardware or software. If you decide to go back to your previous operating system, you’ll need to reinstall it from the recovery or installation media that came with your PC.
Update: Download Windows 8 Setup
Download Windows 8 Developer Preview x86 ESD (en-us)
Download Windows 8 Developer Preview x64 ESD (en-us)