My colleague Mohit has completed some great work on an Exchange integration problem with one of our early 2010 customers. See the results of his work at http://blogs.msdn.com/b/mohits/archive/2010/05/29/integration-of-project-server-2010-and-exchange-2010-2007.aspx . This was a solution in two parts, with one of the issues being the setting of impersonation in Exchange Server 2010, and the requirement to set the scope of the impersonation role with New-ManagementScope and the second was the issue was that if you have multiple servers in your Exchange farm then our TechNet article assumes all servers it finds with the PowerShell command will be Client Access Severs (CAS). Thanks to Luke Kannel at Convergent for his posting that helped resolve this second issue - http://www.tincupsandstring.com/2010/05/12/exchange-2010-and-project-server-2010-integration/ .
Our TechNet documents will be updated shortly.
For the search engines I’ll add the specific error messages you might see. For the first issue you will get “PSError: GeneralExchangeSyncError (40500) System.Web.Services.Protocols.SoapException: The account does not have permission to impersonate the requested user” and the second will give a “Cannot bind argument to parameter ‘Identity’ because it is null.” error.