We have a single 2003 exchange server. Is it possible to install Exchange 2010 on the domain and not affect current 2003 users? I would like to install and setup the cas/hub/mbx to the point where I can do the certificate wizard without pointing the dns to new server. Is this possible?
Here is a Microsoft Resource that allows you to specify the type of Exchange 2010 Implementation that you are doing and provides the recommended course of action.
When you say install Exchange 2010, what roles would you be installing initially? Would you be installing 2010 as a member of the existing Exchange 2003 Org?