Microsoft have released for some time now preinstalled and preconfigured Virtual Images (in Virtual PC VHD format) of Exchange Server and SQL Server for evaluation. The list is expanded to cover many more of MS softwares including ISA Server, BizTalk, System Center, Windows Server 2008, Vista Enterprise and Office 2007. There are also candidates that are time consuming to install and configure like MOSS 2007 & VS 2005 Team System. With these images, all you have to do is download them and run the VHD files with Virtual PC or Virtual Server (both are free from Microsoft). It can’t get easier than this.
At some point I guess all server software will come in this fashion, even for production environments. Whether it is Windows or Linux, Server software are becoming more and more complex to configure and secure that it is only logical for Product companies to give them precooked and ready to eat.
You can download the images from microsoft.com/vpc