Here's what happens when the iBook goes and tries to Install Photosynth:

Unfortunately, we're not cool enough to run on your OS yet. We really wish we had a version of Photosynth that worked cross platform, but for now it only runs on Windows.

Trust us, as soon as we have a Mac version ready, it will be up and available on our site.

I'm not sure if they're mocking me or honestly apologizing, but I do know that either way that that's the most human response I've seen coming from Microsoft to say that something only works in Windows.