Hi,
For Windows, I don't believe there's any change from CS4 to CS5 regarding this optional plug-in. If you already have it, just copy it over. If not, you can get the CS4 optional package and copy it. (http://www.adobe.com/support/downloads/detail.jsp?ftpID=4048)
Make sure to copy the 64 bit into the 64 bit app directory, and the 32 bit into the x86 directory. If it doesn't work, sorry :-P Idon't have a Windows machine at and to test it out. Yes, this will be included in the CS5 posting when it comes out. I'm trying to get info on the ETA for posting.
regards,
steve