The Consumer Preview of Windows 8 is released and can be downloaded from MSDN. If you don't have MSDN go to this link.
Consumer Preview FAQ.
Note before you download: 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