Check this out. Have you ever wanted to try Exchange Server 2007 without a dedicated server? Now you can very easily using Technet’s .VHD downloads.
Simply installed Virtual Server 2005 R2 and download the .VHD file (the virtual machine/virtual image/virtual hard drive) of the product you wish to check out. We have downloadable .VHDs for Exchange Server 2007, SQL Server 2005, and Windows Server 2003 R2 along with accompanying labs to introduce you to the latest technologies in the server product live.
DOWNLOAD VIRTUAL SERVER & THE .VHDs:
http://www.microsoft.com/technet/try/vhd/default.mspx
Kurt Shintaku's Blog 