Well the news is all over the place, from
You can get it from the connect site and read the readme and the installation guide online as well. By the way if you are running Beta 1 and are wondering what you need to do to get onto RC, it’s pretty simply (and the online readme should be updated with this pretty soon):
Uninstall Beta 1
Running the Upgrade Wizard
The last step can be performed by running the wizard from All Programs à Microsoft Commerce Server 2007 à Tools à Upgrade Wizard, or by directly launching the exe from “%Commerce_Server_Root%\Upgrade\Upgrade\CS2007Upgrade.exe".
Hopefully you will be WOWed by what you see.
P.S. - Incase you are wondering about the name change from CS 2006 to CS 2007, you can read more about it in Ryan's post, but in a nutshell it is simple - it is simply a name change and does not affect anything else.