Virtual Server has commonly created a shared disk over the emulated SCSI controller to use for clustered storage. However, Server 2008 clustering doesn’t support parallel SCSI.
But there is light at the end of the tunnel. Server 2008 clustering supports the majority node set model, which means a cluster doesn’t need shared storage. Server 2008 can use node-voting with three nodes or more, or a file-share witness instead of the quorum disk for two-node clusters.
If you want shared storage, the easiest option is probably iSCSI because the iSCSI initiator is built into both Server 2008 and Windows Vista. For the iSCSI target, you may have access to an iSCSI SAN/device, a software solution such as Windows Storage Server, or an add-on iSCSI