Exchange Server 2010 Deployment Assistant allows you to create Exchange Server 2010 on-premises deployment instructions that're customized to your environment. The DA asks you a small set of questions and, based on your answers, it provides a checklist with instructions designed to get you up and running on Ex 2010. In addition to online checklist, you can even print a PDF of your checklist.
Microsoft announce that the "DA has been enhanced to include rich coexistence information for those interested in maintaining some users on-premises and some users hosted by Microsoft Office 365 for enterprises in the cloud. This approach is different than the Simple Exchange Migration (SEM) and Staged Migration options currently offered by Office 365.
As of now, the available scenario is targeted solely at those organizations with a current Exchange 2003 on-premises implementation, but additional scenarios for supporting Exchange 2007 and Exchange 2010 will be coming. The coexistence information is also only available in English at this time."