Reading Jeff's blog i see we just released the November Rosario CTP in VPC format.
If you do decide to download the VPC make sure and check out Brian's post on the best way of using a download manager!
If you are just starting out with Rosario (like me) you might start by downloading the documentation first.
Visual Studio Team System Code Name "Rosario" November 2007 CTP Documentation.
For more information on the CTP (like the new features) make sure and check out Jeff's blog entry:
November Rosario CTP now available!