Just read a post by Mark Harrison about a Microsoft Search Server 2008 Express VHD available for download. The download also comes with a walkthough guide.
The guide gives a hands-on tour of the product, along with useful information for administrators and other IT professionals. You can use the guide and VHD to demonstrate many of the key features of Microsoft Search Server 2008. The VHD includes all of the files and software you need in order to complete the walkthrough. They will provide you with a basic understanding of the configuration, administration, and end-user search capabilities in Microsoft Search Server 2008 Express edition.