The Storage Team Blog about file services and storage features in Windows Server, Windows XP, Windows Vista and Windows 7.
Jose Barreto just posted an article describing different ways to implement Windows Server Failover Clustering with Windows Server 2008 Hyper-V.
The scenarios described include:
1 - Parent-based Failover Clustering with two physical servers 2 - Child-based Failover Clustering with two physical servers3 - Mixed Physical/Virtual Failover Clustering 4 - Failover Clustering with two child partitions on one physical server5 - Standalone demo laptop with Virtual iSCSI SAN
Check the details on each one (including a "before" and "after" diagram for each) athttp://blogs.technet.com/josebda/archive/2008/06/17/windows-server-2008-hyper-v-failover-clustering-options.aspx