Two new documents are now available:

Project Server 2010 Upgrade Paths: that describes the options for upgrading from Project Server 2003 or 2007 to Project Server 2010

http://www.microsoft.com/downloads/details.aspx?displaylang=en&FamilyID=dd993c57-3829-438b-a09d-3e19cbb93e23

Project Portfolio Server 2007 to Project Server 2010 Paths and Considerations: that describes Project Portfolio Server 2007 migration to Project Server 2010

http://www.microsoft.com/downloads/details.aspx?displaylang=en&FamilyID=12e25e2b-fda6-4fda-9f1b-fa39134e26ee