I ran the Exchange Pre-Deployment Analyzer in my Exchange 2003 lab environment. You can use this tool to perform an overall topology readiness scan of your environment. It provides a detailed report that will alert you if there are any issues within your organization, which could prevent you from deploying Exchange 2010. For example, the Exchange Pre-Deployment Analyzer will notify you if you haven't deployed the minimum required Exchange service pack on all your existing Exchange servers.
I guess I don’t have to write "Things to consider” documents anymore :(
You can download this tool from the following location: