Microsoft has released an updated "basic" Deployment Assistant to aid organizations with guiding them through the basic process of implementing Exchange 2010 in an existing Exchange 2003 or Exchange 2007 organization as well as a newly created organization. It does give good information for those organizations that are smaller or only needing some basic information. I think it is a good start for those organizations that are complex in nature or for those that do not have very experienced on site engineers. Of course, I might be a bit biased ;-) based upon my consulting background.
The Deployment Assistant is available at http://technet.microsoft.com/exdeployment2010