Microsoft recently published a two hours online course on Failover Clustering for Windows Server 2008 (formerly known as Longhorn).
You can access this content here and for $39.99, you can spend as much time as you want for the next three years reviewing the content.
This course, Course 6051: Implementing High Availability and Virtualization in Windows Server 2008 is part of a larger group of courses that can be purchased as a group, or you can purchase this individual course separate from any other eLearning course.
Rod Fournier and I are working on very similar material, with much more depth for our ClusterHelp.com course. However, we will not be releasing it until Windows Server 2008 is released to manufacturing. Look for more information here as Windows Server 2008 comes closer to release.