For the ones that after downloading a few download as a zip, you need SkinStudio installed, go to software tab here if you do not, then extract the zip, find the .msstyle file, double click it and SkinStudio will convert it to a WB skin.
Due to limitations of msstyles they will not be as completely skinned as WB skins that are here.
If you move the .theme file to C:\WINDOWS\Resources\Themes, it may apply from Themes in Display Properties, I am not willing to test as I do not want to set everything to XP default in order to do so.