It took me a while to find the plug in (I bought the Master Collection and Adobe hid this file on the Content disc (in a supplemental package that did not appear to have anything to do with the programs). The plug in had directions, but the directions were not correct. I finally figured out how to make it work, but I thought I better post it here in case other were having the same problem. Note: my directions are not endorsed by Adobe and differ from their instructions. On the other hand, my directions worked for me and Adobe's did not.
First, make sure your copy of Photoshop is closed.
Second, copy the plug in to C:\Program Files\Common Files\Adobe\Plug-Ins\CS3\File Formats.
Third, copy the other six profile files (that end with .icm) to C:\Program Files\Common Files\Adobe\Color\Profiles.
Finally, restart Photoshop.
Once this was done, Photoshop could load my Photo CD files. In practice, a few files did not work, I do not know if this is Adobe’s fault or if a few files became corrupt over time. At least I can view the majority of my files. I also started saving them in more modern formats for future use.
It is sad when Adobe makes me wish they at least met Microsoft’s standards for usefulness. It says something about both how much Microsoft has improved over the years and how much Adobe has declined.