I often get asked the question by customers on how to find the newly released hotfixes for Cluster and Hyper-V or the customer wants to know what hotfixes are out there. We have 3 Wiki pages that will make life easier for you when looking for hotfixes for Windows Server 2008 R2 Cluster and Hyper-V. You can also setup an RSS Subscription to the Wiki page so you can the updated Wiki page in your favorite RSS app or Outlook.
Hyper-V: Update List for Windows Server 2008 R2 (en-US)
List of Cluster Hotfixes for Windows Server 2008 R2
List of Failover Cluster Packages Updated After the Release of Windows Server 2008 R2 Service Pack 1 (SP1)
Support Escalation Engineer
Microsoft Enterprise Platform Support
High Availability Team