Virtual PC 2007
This update to Microsoft's virtualization software is currently in public beta (go to get access to the bits to try it out yourself) and in this release, you get support for virtualization assisted by your processor and the ability to use Windows Vista as the host, the guest or both. The final release of Virtual PC 2007 should, aptly, be in the second half of 2007.
Windows Server 2003 Service Pack 2
This service pack has been in beta for a while and is now at the release candidate stage. With this release, you get a roll up of all critical and security hot fixes, but you also get support for Windows Deployment Services, a necessary installation if you want to deploy installations of Windows Vista on clients connected to your network.
This release appears to be well on track, and the target, according to the Windows Service Pack Road Map, is the first quarter of 2007, so we should see this available for download (and, of course, slipstreamed into new channel copies of Windows Server 2003) within the next couple of months.