I have learned (via William) that there is a limited time offer of a free Exchange Server 2007 Unified Messaging course that you can take online if interested.
From the course page:
Title: Clinic 5091: Introduction to Microsoft Exchange Server 2007 Unified Messaging
Course Type: Self-paced Course
Available Offline: Yes
Estimated Time of Completion: 2 Hours
In this online clinic, you are introduced to the new Unified Messaging features and functionalities in Exchange Server 2007. In addition, you learn how telephony and Unified Messaging can be integrated in Exchange Server 2007. This online clinic is composed of a rich multimedia experience. It is intended for IT Professionals who are interested in telephony or Unified Messaging.
At this time I do not know how long this will be available for free but I figured some of you might like it!