JPEG 2000 plug-in for Windows
Here's the link, but notice that it's now sold as part of a package, along with the Camera Raw plugin and sells for a hefty hundred clams. For a short while - quite a while ago - it was available as a download for PSE 1. I couldn't find anything on the Adobe site about that, so I think it's been pulled as an offering. There are versions for both Win and Mac, so maybe somebody downloaded the freebie and would share. People here on the forum discouraged me from getting it when it was available because the technology is so new that it's not really good for much. If you convert an image to that format and send it off to someone else, they can't open it unless they have the JPEG 2000 plug in, too.