Terms you'll need to understand:
Clustering
Failover
Failback
Online backup
Offline backup
Cluster
Cluster resource
Cluster resource group
Cluster virtual server
Convergence
Heartbeat
Node
Quorum disk
Techniques you'll need to master:
Configuring and managing Exchange server clusters
Troubleshooting Exchange server clusters
Planning and performing Exchange backups
Planning and performing Exchange restorations
Removing Exchange servers from the Exchange organization