This is a nice touch, the pre-canned VHD's are now available for pre-release versions of SQL Server 2008 CTP4 http://www.microsoft.com/downloads/details.aspx?FamilyID=6a39affa-db6e-48a9-82e4-4efd6705f4a6&DisplayLang=en and Windows Server 2008 Beta 3 http://www.microsoft.com/downloads/details.aspx?familyid=9AA65956-4A13-46A3-9711-82939A041792&displaylang=en.  Note: the VHD download is split into approximately four compressed .rar files.