For those who use IBM hardware, there is some great news today.  IBM has released the Microsoft Assessment Planning Tool for IBM, which is based on the existing Microsoft Assessment Planning Tool.  This tools provides specific guidance on how to consolidate and virtualize workloads on IBM System x and BladeCenter servers.  If you use IBM systems, you should check this out.  You can get the tool from

http://www-947.ibm.com/systems/support/supportsite.wss/docdisplay?lndocid=SYST-MANAGE&brandind=5000016

Note, this page is full of IBM resources for Microsoft Systems Management Solutions, including IBM PRO packs for Virtual Machine Manager.