Just saw this on the internal VSTS alias!

"The Team Foundation Server Release Candidate bits including upgrade utilities are now available for download available

from the MSDN Subscriber Download site: http://msdn.microsoft.com/subscriptions/.

To upgrade from Beta3 Refresh to RTM, please follow these steps:

Backup your server and copy the data to a safe location (that should be a no-brainer).

Download the Team Foundation Server RC from

MSDN Subscriber Downloads 

Download the Upgrade Utility.

Uninstall Team Foundation Server Beta 3 Refresh.

Follow the upgrade instructions, which are included with the Upgrade Utility.

Install Team Foundation Server RC.

Complete the post install upgrade instructions, which are included with the Upgrade Utility.

For a reference to the major changes since Beta3 refresh, please see Jeff's  blog. "

Congratulations to everyone involved in this tremendous effort!