The Hyper-V Planning and Deployment Guide has just been updated with information about security best practices (including AzMan) and backup:

Planning for Hyper-V Security

Planning for Backup

Using Authorization Manager for Hyper-V Security

Configure Hyper-V for Role-based Access Control

Did we miss anything for these topics? What is the next topic you need? Leave comments.

Additional Resources:

Hyper-V Attack Surface Reference Workbook
The Windows Server 2008 Security Guide includes a spreadsheet you can download that lists all the attack surfaces for Windows Server 2008. This guide was initially published before Hyper-V role RTM. When the Security Guide is updated, a new worksheet in the Attack Surface Reference Workbook will be added that lists the attack surfaces for Hyper-V. Until then, you can find the same information in the Hyper-V Attack Surface Reference Workbook, available for download at Server 2008 Hyper-V Attack Surface Reference.xlsx    

Virtualization Security Best Practices Podcast:

Windows Server Virtualization and Windows Hypervisor:

"Security in a Virtual World":