Verified answer

I found some OS X icons here:

http://www.catswhocode.com/blog/os/gnu-linux/10-ic...

And here:

http://linux.softpedia.com/get/Desktop-Environment...

You can actually look around for Vista Icons for Gnome -- Gnome is the desktop Ubuntu uses and several other distros, including debian which it's derived from, use it by default (though I'm writing this on Debian with KDE and no Gnome). Read this page:

http://ubuntuforums.org/showthread.php?t=442976

This is a howto you might find useful:

http://www.go2linux.org/gnome-theme-customize

And here are some themes:

http://gnome-themes.org/index.php/mode,browse/type...

Sorry, I can't find any specific vista icons.

i wish i could help but i've never gotten to get ubuntu to work. Maybe if you helped me get ubuntu to work i can help you