The major differences between Project Server 2010 and Office Project Server 2007 are the following:
(1) Project Server 2010 requires Microsoft SharePoint Server 2010 to be installed on the computer running Project Server and on all Project Web App servers within a SharePoint farm.
(2) The PSI includes both the Windows Communication Foundation (WCF) interface and the ASMX interface for Web services.
(3) The Project Server workflow platform is integrated in the PSI, business object layer, and DAL, and built on Windows Workflow Foundation (WF) in the SharePoint platform.
(4) Project Server task, assignment, and assignment status data is integrated with Microsoft Exchange Server, instead of with a Microsoft Outlook add-in.