Many people move from XP to Vista not for software compatibility but for the "look". It is possible to move change the theme on Windows XP to Vista. XP does not need to stay blue, silver, or olive green.

Windows blinds allows you to choose from hundreds of different styles. Dark themes to cloudy themes and even themes of your favorite video games. Keep in mind that more computer memory will be used and it is nice to have at least a gigabyte of RAM before you do change the theme.

Follow up:

The free way to do this is to download the Vista Transformation Pack 9.0.1. This can be found at www.softpedia.com. I prefer to do it the free way if all you want to do is make Windows XP look like the Vista theme.

However, Windows Blinds does offer hundreds of different themes for Windows XP and Vista. Check them out at http://www.stardock.com/products/windowblinds/.