The wait is over, you can now download from here. Extra details can be found here and in the FAQ from where I pulled out these details on the new features. Bink.nu also has more of a write up than time allows me to produce today
Virtual Server 2005 R2 SP1 includes the following new capabilities:
Virtual Server 2005 R2 SP1 Enterprise Edition can be installed on servers with up to 32 physical processors.
Virtual Server host clustering. Support for host-to-host connectivity lets you cluster all virtual machines running on a host.
iSCSI support. iSCSI clustering enables guest-to-guest connectivity across physical machines.
x64 support. Virtual Server runs natively within a 64-bit Windows host operating system, providing increased performance and memory headroom.
Enhanced PXE booting. PXE boot support has been added to the virtual machine network adapter. This means that when the appropriate network infrastructure is in place, you can perform a network installation of a guest operating system in the same way as physical servers.
Other improvements. Virtual Server now includes improved hyperthreading, support for F6 Disk (SCSI driver), Active Directory integration using service connection points, and virtual disk pre-compactor functionality.
New Features in Virtual Server R2 SP1
Supports both Intel Virtualization Technology (Intel VT) and AMD Virtualization (AMD-V) hardware-assisted virtualization.
VHD Mount Command-line Tool and APIs
Provides the ability to mount a virtual hard disk file (.vhd file) as a virtual disk device on another operating system.
Support for Volume Shadow Copy Service
Allows back-up of Virtual Server and its running virtual machines without needing to install backup agents inside the guest operating system of the virtual machines.
Larger default size for dynamically expanding virtual hard disks
The default size for dynamically expanding virtual hard disks has been changed from 16 GB to 127 GB, making the VHD file format even more useful for enterprise production, test, and disaster-recovery workloads.
Support for greater than 64 virtual machines on x64-based hosts
Virtual Server can run more than 64 virtual machines on x64-based hosts. The 64 virtual machine limit remains when running on 32-bit hosts.
Host clustering step-by-step guide
Host clustering allows you to extend the high-availability benefits of clustering to non-cluster-aware applications and workloads.
Virtual SCSI fix for Linux guests
This fix resolves an issue some customers encountered when trying to install certain Linux distributions inside a virtual machine on the emulated SCSI bus.
VMRC ActiveX control and Internet Explorer Security Zones
The Virtual Machine Remote Control (VMRC) ActiveX control now uses the security zone information in Internet Explorer to determine whether to prompt you for your credentials when you load the control.
Service Publication using Active Directory Service Connection Points
Virtual Server service now publishes its binding information in Active Directory as a Service Connection Point (SCP) object.