Ok I have downloaded it and extracted it. But when I tried to install it I got an error message saying "Longhorn Transformation Pack does now support this OS". So what do I do now?

Bump =\

Are you trying to install the Vista Transformation Pack v6? It supports Windows XP. It may not have been updated yet for SP3 - maybe that's the problem? Checked their website for info?

I just went back to the website and looked for one that works with Vista and I didn't find any.

Yeah, the Vista Transformation Pack only works on XP - to make it look like Vista. If you have Vista already, you don't need it.

I think there is an OS-X Transformation Pack for Vista out there somewhere...