Previewed briefly last year, Microsoft is now giving consumers a bigger bite of the Windows pie, with a downloadable copy of Windows 8 available free from today.

The upcoming version of Windows – now in its eighth release – will likely arrive later this year with a heavy emphasis on touchscreen design, one of the factors missing from the current iteration of Windows and seen as something that Microsoft will need if it wants to compete in the tablet wars.

Borrowing design from both the Windows Phone 7 and Xbox interface, the “Metro UI” look used for Windows 8 will come from squares and rectangles, big clear fonts, and bold colours.

This idea has a very “touch-friendly” feel to it, but Microsoft also promises that people without touch screens will be able to use the Windows 8 preview, with both keyboard and mouse supported.

While this copy of Windows is currently free (and large, with a download of at least 2.5GB), we don’t recommend everyone just go and grab a copy. At this time, Windows 8 is a preview edition, meaning that not all software will work on it, some of your hardware – like sound cards or graphics chipsets – may not function properly, and generally it’s not ready for prime time use.

But if you’re eager to get your hands dirty and see the future of Windows, grab a copy of a virtualisation software for your operating system. Parallels has apps available for both Mac OS and Windows, as well as VMWare and VirtualBox.

Each of these applications will make a “virtual computer” inside your current computer, allowing you to install the Windows 8 preview without it destroying or writing over your current operating system.