Windows 8,which introduced a new version is for developers or theso-called developer preview. However, that does not mean you can not try it. Everyone can try it for free by downloading from the site that has been provided by Microsoft. There are three versionsavailablefor each of two 64 bit systems and one for 32 bit. Here are threeversions ofthe following provided links to download each version.
The file size of each of the above options vary, ranging from 2.8 GB to the very top, 3.6GB for the middle and 4.8 GB for the lowest. As stated by Microsoft, Windows 8developer preview version is not final, so after they finish downloading, you should store them on a CD or flash.