I checked today with the Microsoft Action Pack Regional Service Center for the Unites States on what the availability of Windows 8 will be for US Partners who have current Action Pack subscriptions. We will be getting usage rights for 10 licenses of Windows 8 Professional. Available August 20, 2012.
Also check out release dates here on the Windows Team Blog (thanks to Brandon LeBlanc):
People will be able get Windows 8 starting on October 26th either by upgrading for $39.99 or on a new PC or device. And if you buy an eligible Windows 7 PC today, you will be able to purchase an upgrade to Windows 8 Pro for $14.99 (U.S.) through the Windows Upgrade Offer.
However, we have a number of programs that provides various audiences early access to the Windows 8 RTM code to help prepare for Windows 8 as it enters the marketplace this fall:
Please note: if a program you are in is not mentioned, please be patient as dates for Windows 8 RTM code availability for other programs will be communicated when the information becomes available.