Windows 8 Consumer Preview officially went live on the morning of Leap Day, February 29, 2012, although the actual download speeds for the large ISO files (2.5GB for the 32-bit edition, 3.3GB for the 64-bit version) have been times sluggish due to heavy enthusiast demand.
Nevertheless, Windows 8 Consumer Preview can be installed as an upgrade over the Developer Preview hat Microsoft shipped last September and can even be upgraded over Windows 7, Vista and even Windows XP RTM builds.
Image source: AnandTech
As for a physical product announcement, Microsoft used the backdrop of Mobile World Congress 2012 in Barcelona, Spain to hold an onstage demonstration of the Consumer Preview on a variety of x86 and ARM-based devices. Most interestingly, of course, were the company's demonstrations on Nvidia's Tegra 3, Qualcomm's Snapdragon S4 Krait and Texas Instruments' OMAP 5 and Intel's Clover Trail platform. According to sources at the event, all four of these platform will be support Windows 8 at launch, but not all will be available when the OS launches.
Microsoft Windows 8 Consumer Preview "upgrade" packs can be downloaded here, while the "clean installation" .ISO files can be downloaded here.