Today is a big day for millions of Technet and MSDN subscribers.
You should be able to download the final versions of Windows 8 via your subscription access at some point today.
This applies only to developers and IT professionals.
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.