A new upgrade package for upgrading Team Foundation Server Beta 3 Refresh to RC is now available for download, which includes a revised upgrade guide and utilities that address issues encountered in the first release. If you haven't upgraded yet, be sure to get the latest.
As part of the upgrade package, you’ll find a lengthy (but informative) Word document that you would be wise to read before starting your upgrade. We took the trouble to write such a comprehensive document to ensure you had the best upgrade experience possible. Please read it first.
Rob Caron : RTFM - Upgrade Guide.