CRM 2011 just released today and you may download it on the Download Center.   There will be no in place upgrade from beta to RC at this moment.  You have two options at this moment.

Option 1: Backup your database, create a new RC environment, then import/upgrade the beta org into RC.

Option 2: Uninstall beta, reinstall it and using the connect to existing data base option.

You may download the bit here.

CRM 2011 Server RC

CRM 2011 Outlook Client

Language Pack

Email Router


SharePoint Connector