http://msdn.microsoft.com/en-us/evalcenter/jj554510.aspx MS are letting you download it now as a trial just getting my copy 7 mins to download
students can ask their institutions for a dreamspark account and get Win8 preview with apps and a bundle of other Microsoft software too e.g. Office Suite, Visual Studio, Server OS, etc
how much is it ? $14.99? I like more Rams because I want a faster windows. If I upgrade from win7 to win8, will everything (files, program installed) be alright or have to make a backup of them
The free copy is a 90 day trial so dont use that only to test but the full version should upgrade win7 to 8 but a backup is all ways good