Here are the resources noted in the webcast from earlier today....
Microsoft Virtualization Home Page - This is our main resource site for all things virtualized.
Virtualization Calculators - Use these calculators to help determine your hardware needs when consolidating servers
Technet Windows 2008 Virtualization Site - Most of the information here is beat or refers to betas. Expect this to get deeper as we get closer to the Windows 2008 Server Launch date.
System Center Virtual Machine Manager Site - The Main landing page for SCVMM
Virtual Server Site - Virtual Server is the add-on application for Windows 2003 that allows us to virtualize servers and workloads
Virtual PC Site - Virtual PC is great for testing, labs, demonstrations and lower end virtualization efforts.
SoftGrid Home Page - If all you need to do is virtualize a specific application, SoftGrid is the answer
Chris has posted a great list of sites to visit for Virtualization. Microsoft Virtualization Home Page