Just an FYI for those using CS4 and NIK products. There is currently a problem with the windows 32 bit compatibility. The current fix is to download the current version of DFine (15 day trial) and install it to update some critical files. If you don't want DFine you can then uninstall it. That fixes the other products such as Color and Silver effects.
This really pi$$ed me off because it took me an hour to figure out what the problem was. I just upgraded to CS4 this afternoon, and then had to put all my plugins back in. CS4 then acted corrupted, with all the menu options greyed out, and it wouldn't close. I had to do it all over and do everything one at a time to see what was causing it, then I found the notice on the NIK site.