There have been some Mac emulators for the PC but the problem is that Apple will not license its OS for non-Apple hardware. Microsoft is less fussy and will license Windows for PC emulators. I have seen Mac emulators on the net for OS 8 but not for higher OS versions. I would stick to PCs for PC software and Apples for Apple software.
OSX is based on Debian Linux and this will certainly run on Intel hardware. The Apple 'Aqua' X Windows interface though will not, purely because Apple don't release it. One might argue that they'd make more money (and kill Windows a little bit) if they did, but they don't.