Windows 8 Consumer Preview is here (build 8250). Feel free to download and test:

http://windows.microsoft.com/en-US/windows-8/consumer-preview

http://windows.microsoft.com/en-US/windows-8/download

Direct download links to ISO images with Windows 8 Consumer Preview:

English
64-bit (x64)                    Download (3.3 GB)
Sha 1 hash — 1288519C5035BCAC83CBFA23A33038CCF5522749
32-bit (x86)                    Download (2.5 GB)
Sha 1 hash — E91ED665B01A46F4344C36D9D88C8BF78E9A1B39

One Product Key for all:   DNJXJ-7XBW8-2378T-X22TX-BKG7J
Windows 8 CP will expire on January 15, 2013.

Here you can find more links to more languages:
http://windows.microsoft.com/en-US/windows-8/iso

Big change: the Start button has gone forever :)