It’s easy so long as you can rummage together mostly-equivalent hardware that Apple uses. Mainly because of built-in Mac OS X driver support, otherwise it can escalate into the more tedious realm. When I say that, I mean you’ll have to know the manufacturer and model number of certain pieces of hardware or chipsets. There are a good many 3rd party OSX86 drivers which have been written for non-Apple branded hardware, just not for everything out there in the diverse PC ecosystem.
Friend and I tried it once on his PC a little over 2 years ago, it worked fine except for the lack of available 3rd party OS X drivers needed for his motherboard. At the time he had a nForce chipset, which had no available drivers for OS X, so he was unable to use some basics like Ethernet. Since Apple uses Intel hardware, I’d probably recommend that over AMD, even though I can’t remember now if we had to do something else regarding AMD CPUs. And of course video cards have always been the bane of being a Mac user. If the video make and model is anything Apple has ever written a driver for, it will likely work, otherwise you’ll have to look around.
It might be a bit easier now than it was back then though.
