Since Vista hasn't shipped yet for consumer purchase, we haven't been in too big of a rush to release a patch. Episode 2 is Vista-friendly right out of the 'box', but Culture Shock hasn't been updated yet. We will update it soon, though.
That said, all that's broken in Culture Shock is that the activation resets every reboot, so if you want to play through the game now, you can do it as long as you don't reboot before finishing. That's pretty lame, obviously, but it works as a temporary solution.