The Developer Preview is a prebeta version showing off the operating system at its current stage. Though technically designed for developers, no registration is required, so anyone can download and install it.
• Windows 8 debuts at Microsoft Build (live blog)
• An early, first look at Windows 8 (hands-on)
• Take an early tour of Windows 8 (photos)
• Windows 8 to offer both Metro and desktop interface
The Windows 8 Preview is being offered in three different packages--a 64-bit version with various developer tools, a 64-bit version of just the operating system, and a 32-bit version of the OS.
All three come as ISO files--image files of the contents of a CD or DVD. Since each of the packages is several gigabytes in size, you'll need a DVD if you want to burn the files to a disc.
In Windows 7, you can burn the ISO file to a DVD by double-clicking it to open the Windows Disc Image Burner. For older operating systems, you can use a tool such as ISO Recorder to burn the file. Alternatively, you can use such utilities as Virtual CloneDrive or Daemon Tools to "mount" the ISO file as a drive, eliminating the need to burn it onto a disc.
Since this is a prebeta version, you'll want to install the OS on a spare PC or in a virtual environment so that it doesn't interfere with your production or work machine.
Watch the Video first Look Walkthrough installing it