However, there have been many misconceptions on whether it is legal to use Apple software of a regular PC. The clear cut answer is no.
Psystar is attacked for selling hack macintosh's
The company Psystar has had a lawsuit from Apple filed against them because the company was openly selling computers loaded with a Mac OS. From Wikipedia:
Psystar Corporation is a Miami, Florida based company which sold "Open Computers". These computers, first announced in April 2008, had the option to be pre-installed with Mac OS X Leopard, making them the first commercially distributed 'hacked' Macintosh computers. In November 2009, a U.S. Federal District Court ruled Psystar violated Apple's copyrights in doing so.
Psystar Corporation is currently having a struggle with Apple, and the journey has involved filing for bankrupty and court complications.
What if I am just using the computer for private use (no commercial aspect)?
While a private user will not be under as much stress from Apple as Psystar, it doesn't make using a Mac OS on a PC any more legal. This is a segment for a EULA for a Mac OSX operating system- important bits are bolded for emphasis
2. Permitted License Uses and Restrictions.
A. Single Use License. Subject to the terms and conditions of this License, unless you have purchased a Family Pack or Upgrade license for the Apple Software, you are granted a limited non-exclusive license to install, use and run one (1) copy of the Apple Software on a single Apple-branded computer at a time. You agree not to install, use or run the Apple Software on any non-Apple-branded computer, or to enable others to do so. This License does not allow the Apple
Software to exist on more than one computer at a time, and you may not make the Apple Software available over a network where it could be used by multiple
computers at the same time.
So it can be seen that hackintosh's is not legal (although one probably won't be sent to jail for it). Will this stop people from doing it..... probably not.