Deployment
Planning and Deploying Exchange 2010 SP1 in your Organization
Use these guides to help you plan and prepare for your Exchange Server 2010 deployment.
Microsoft Exchange Server 2010 Deployment Assistant
The  Microsoft Exchange Server 2010 Deployment Assistant allows an  Administrator to create Exchange 2010 on-premise deployment instructions  that are customized to their environment. The Assistant asks a small  set of questions, and based on the answers, it provides a finite set of  instructions that are designed to get an Administrator up and running on  Exchange 2010. Visit it today to see how you can deploy Exchange Server  2010 in your environment!
Exchange 2007 – Planning Roadmap for Upgrade and Coexistence
You  can deploy Microsoft Exchange Server 2010 in an existing Microsoft  Exchange Server 2007 organization. This topic provides an overview of  the planning considerations and configuration steps that you must take  when Exchange 2010 will coexist with Exchange 2007.

Administration
A Roadmap for Exchange 2010 SP1 Features
This roadmap helps you get acquainted with all the features in Microsoft Exchange Server 2010.
New Transport Functionality in Exchange 2010 SP1
This  library article includes and overview of new functionality for  Transport in Exchange 2010 SP1, including message tracking, throttling  enhancements, SMTP failover, and more.
Security
Understanding Permissions
Microsoft  Exchange Server 2010 includes a large set of pre-defined permissions,  based on the Role Based Access Control (RBAC) permissions model, that  you can use right away to easily grant permissions to your  administrators and users.