ReactOS (an open source OS aimed to be a binary compatible with Windows) is now supporitng Parallels: http://www.reactos.org/en/news_page_28.html
I can get the ReactOS live CD image to work, but when I try to actually install from the install CD image, the install acts like it's working but then hangs formatting the hard drive. Does anyone have the install working? Could you provide some details about what OS you chose in Parallels, etc.?
ReactOS working for me Donnie, I have Parallels running on my Intel Mac mini with 512 MB of RAM. I selected "other" / "other" for ReactOS, and backed the memory allocation down to 32 MB or so since I haven't upgraded RAM yet. (Try running the SMP version of Folding@Home on this puppy if you REALLY want to make it useless for anything else at the same time!) If I recall correctly, the installation process (possibly the formatting) was going extremely slowly with the default amount of RAM. That may or may not be what you're seeing. I was also bit by the "55AA" bug (after the first installation, rebooting claims the VHB or some such doesn't have the correct signature; this is a known issue with ReactOS, the workaround is to reinstall), then I ran into some other problem which necessitated reinstalling a time or two more. But I now have a stable install that I can bring up and shut down (though it doesn't go as far as powering off the VM). The ReactOS wizard is unable to install the audio / bridge / VGA drivers it wants to, and I haven't attempted installing the Parallels tools on the ReactOS machine; not sure how much of this will, or can, work at this stage, so at the moment I haven't even attempted to install and run Firefox on it. (My goal with Parallels was to run things like Windows-only USB software for my cell phone, WMP 9 to download audiobooks from the library to my wife's MP3 player, and videos over the Web that refuse to run on the Mac or Linux, but I don't have a full version of Windows 2000 or better which is needed for most of these tasks. I suspect it will be a looooooooooong time before ReactOS makes it that far, but it's still an interesting exercise!) -Charles