Here are the registration links to an OCS 2007 Learning Series:
Module 1: OCS Architecture details the system architecture that is used by OCS 2007, OCS fundamentals, server roles, component dependencies, planning and deployment scenarios.
Module 2: OCS IM Presence Clients describes the rich presence advancement that Office Communications Server is delivering as well as Office Communicator clients, and deployment scenarios.
Module 3: OCS Conferencing illustrates the new on-premise conferencing capability within OCS 2007 and the differences between LiveMeeting Service and on-premise capability. This module also differentiates conferencing clients and requirements
Module 4: OCS Management and Troubleshooting articulates the new management tools and techniques for troubleshooting OCS 2007, and for identifying any deployment problems.
Module 5: OCS Compliance details the features that OCS 2007 provides to help deliver compliance scenarios, as well as tools and techniques for reporting information.
Module 6: OCS and Exchange UM explains the interaction of OCS 2007 and Exchange 2007 Unified Messaging, details the environment, dial-plan integration, and steps required to add OCS 2007 to Exchange UM infrastructure.