The final version of Windows 8, known as the Release to Manufacturing (RTM) version is now available to download for MSDN and TechNet subscribers.
Although the final bits are available to Microsoft's developer and IT professional subscribers, consumers will have to wait until October 26th to purchase a copy online or in store. Alongside the early Windows 8 availability, Microsoft is also launching a final version of its Windows Store today opening it up to additional developers. Microsoft will be hoping that its early release today will fuel new apps over the coming weeks and months so we should start to see even more Windows 8 style apps available in the Store in preparation for October 26th.
Release timeline for Windows 8:
August 15th: Developers will be able to download the final version of Windows 8 via your MSDN subscriptions.
August 15th: IT professionals testing Windows 8 in organizations will be able to access the final version of Windows 8 through your TechNet subscriptions.
August 16th: Customers with existing Microsoft Software Assurance for Windows will be able to download Windows 8 Enterprise edition through the Volume License Service Center (VLSC), allowing you to test, pilot and begin adopting Windows 8 Enterprise within your organization.
August 16th: Microsoft Partner Network members will have access to Windows 8.
August 20th: Microsoft Action Pack Providers (MAPS) receive access to Windows 8.
September 1st: Volume License customers without Software Assurance will be able to purchase Windows 8 through Microsoft Volume License Resellers.
October 26th: General availability.
Download Windows 8: MSDN | TechNet