Microsoft has released an Release Preview version of it upcoming OS, Windows 8, Release Preview is nothing but just an RC build or you can say Release Candidate, its an testing build and cant be install as your primary OS.
This release is available in 13 languages, its available in Arabic, English, Chinese (Simplified), Chinese (Traditional), French, German, Japanese, Korean, Portuguese (Brazil), Russian, Spanish, Swedish, and Turkish.
You can download Setup of Windows 8 and it will check your system for capability and if its capable then it will download the appropriate version of Windows according to your computer architecture (32 Bit or 64 Bit).
If you wanna install via DVD or USB or you wanna install it on more than one computer then you can download ISO file and burn it write DVD or make a bootable USB.
This build is valid till January 15th, 2013.And while installation you will be needed an registration key which is as follows :-