Yesterday Microsoft has released Windows 8 Release Preview if you’ve not downloaded ISO image(s) till now you can download now from here. If you try to install it on your Computer with “Web Installer” provided by Microsoft then setup automatically provides the key, we don’t think all users have enough bandwidth and internet connection speed to install Windows 8 RP online, online setup is a long process, if something fails in the middle due to power failure we need to restart it from the beginning, avoid this and its better to download ISO image and burn it to DVD and boot it as first device and run the setup.
During the Windows 8 RP setup, you’ll asked to enter the product key, if you don’t type it the installation won’t continue and further more this product key is necessary in future as setup asks you again when you reinstall Release Preview, so it’s better for to you note down the key on paper or on installation media such as DVD.
But where is the key? has Microsoft provided it? yes Microsoft published Win8 Release Preview’s Product key on RP FAQ’s page as well as on ISO images download page.
Here is the Product key of Windows 8 Release Preview