A Step-by-step guide for using MSCS clusters to host Virtual Server guests was just released: http://www.microsoft.com/downloads/details.aspx?FamilyID=09cc042b-154f-4eba-a548-89282d6eb1b3&displaylang=en
Here’s the overview:
Virtual Server host clustering is a way of combining Microsoft® Virtual Server 2005 R2 with the server cluster feature in Microsoft Windows Server™ 2003. This document describes a simple configuration in which you use Microsoft Virtual Server 2005 R2 to configure one guest operating system, and configure a server cluster that has two servers (nodes), either of which can support the guest if the other server is down. You can create this configuration and then, by carefully following the pattern of the configuration, develop a host cluster with additional guests or additional nodes.