[sblock=Rambling on Running the CB on other systems]
It will probably never run on Mac OS X or Linux. The application uses .NET with WPF. While .NET is implemented for Unix/Linux via the Mono project, the Mono project has publicly stated they will not implement the WPF part of .NET. (I kinda understand why - it would probably be enormously difficult to do so, since the OS foundations are so different).
I also get why the WotC developers used .NET and WPF. It's awesome to work with it. (I do it at work.)
Unless someone at the Mono project has a change of heart or decides to create a "spin-off" with WPF, you can't hope for much.
Another hope is that something like Wine or Crossover manage to replicate enough of the Windows platform so that .NET works there fully. But that sounds no easier than the Mono thing.
And the third hope would be that the WotC developers would throw away their entire coding base and interface design and implement the app in Java or even something native with tweaks to run it on multiple systems (there are applications like that, and there are also frameworks like QT that can help you there.) A twist that might allow them to retain much of the codebase and also design might be to switch from WPF to Silverlight, plugins for which should be available for Windows, Linux (via Mono, IIRC) and Mac OS X.
On Mac OS X, Parallels might be able to deal with .NET and WPF applications, but I am not sure it does so. Parallels uses a Virtual Machine to run Windows in and has only limited graphical capabiltiies. BootCamp definitely works. Both solutions require buying a Windows License, and Bootcamp requires you to reboot.
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I am not sure, but aren't the files XML? Theoretically, it should be possible to create an application that displays these files on screen. But that would not replicate you the look and feel of the files. Maybe you could try using a CSS file to do that, but that's still a lot of manual work to implement first. I don't think anyone has tried that so far, and it might not be sufficient.