Mac OS X requires Mac-specific hardware. As such, it is not possible to run OS X on hardware which isn't running a compatible version of Open Firmware without cracking OS X. OTOH, you can run Mac OS =< 9.x in a virtual machine, such as in SheepShaver in Linux.
PearPC, an open powerPC emulator, will run OS-X on windows and POSIX systems. Your system is fast enough to run it usably but it will be slower than native speed.
Look on the link, it is possible to run on a PC properly, you just need the right hardware, most ATi cards aint supported, heaps for Nvidia, same trend as Linux :p
Look at the Hardware Compatability list, this will tell you if you can get your computer to run Mac OSX withought Pear PC.