HOW TO: Get the Vista Experience for Free
You can get a relatively accurate taste of how it will feel to run Windows Vista without actually 
buying it. Microsoft doesn’t want you to know this, but you can actually emulate Windows Vista at home using only WinXP or Win2k machine and some freely available tools. Here is how you do it.
You will need the following: Terminally Incoherent » Blog Archive » How to get the Vista Experience for Free