Its been trivial for years to run Windows on a Mac, thanks to Connectix (now Microsoft's) Virtual PC. Now Leander Kahney reports that a couple of German comp-sci students have gotten the Mac OS to run in emulation under Windows via their PearPC project: OS X Makes Slow Debut on PC

Developed by Sebastian Biallas and Stefan Weyergraf, a pair of 23-year-old computer students from Aachen, Germany, PearPC re-creates in software the PowerPC architecture, the hardware used in Apple's Macs. The free, open-source software allows Intel- and AMD-based PCs to run several operating systems compatible with the PowerPC, including Mandrake Linux, BSD, Darwin and, most importantly, Apple's Mac OS X. Users can download and install a copy of PearPC, and then install a boxed copy of OS X, which can be purchased from Apple for $130.

Be warned that they're at v0.1 but for the truly adventurous: http://pearpc.sourceforge.net/index.html. I like this convergence of operating systems. Just this very morning I installed Microsoft's Remote Desktop Connection Client to be able to admin some machines at work via my Mac from home (far easier than actually taking the time to pull my PC out from under the desk where it's been serving as a mid-priced footstool for the last three months). RDCC isn't speedy either but it certainly does work nicely.