The final version is available at the "Description of the update for the release version of the Hyper-V technology for Windows Server 2008" web page. The main update is a 64-bit file, which includes the Hyper-V components and integration services, and the Hyper-V RTM Integration Services for 32-bit clients. The 64-bit update is at the Microsoft Download Center "Update for Windows Server 2008 x64 Edition" web page, and the 32-bit update is at the "Update for Windows Server 2008" web page.
Remember that the final version of Server 2008 shipped with Hyper-V Beta 3, so any Server 2008 Hyper-V servers and guest OSs should be updated with the final Hyper-V code. On Server 2008 child partitions (guest VMs), run the relevant architecture update, which will prompt you to update the child machine. For other child-partition OSs, run the Insert Integration Services Setup Disk option to install the integration services. The integration services provide the child partitions with access to the Virtual Machine Bus (VMBus), which supplies the non-emulated hardware and vastly improved performance. You'll have to reboot the child partitions after installing the integration services update.
If you’re upgrading from the Hyper-V Beta that shipped with Server 2008 RTM, you must recreate your VMs and all of their settings. If you’re upgrading from RC0 or later, a re-creation isn’t necessary.
The list of supported OSs has grown with the Hyper-V RTM release, and includes 32-bit and 64-bit child partitions running Server 2008, Vista, XP, and Server 2003. The 32-bit Server 2000 and SUSE Linux are also supported. For full details of processor-limitations and service-pack requirements, see www.microsoft.com/windowsserver2008/en/us/hyperv-supported-guest-os.aspx.