There's more to a computer than its microprocessor. In the case of Mac OS X, Apple controls the entire in-box hardware ecosystem, and therefore only warrants that OS X will run on its own machines.
Apple employs some additional hardware, and Mac OS X checks for that hardware.
There are "hackintoshes" available -- that is, there are ways to hack OS X into running on some PCs. I was sort-of successfully running one as an alternative boot on my last PC for a while (no networking nor audio). This is, however, a violation of Apple's end user licensing agreement, and software updates often break these deployments.
In any event, I'm not aware any virtualized hackintosh solution at this point. My experience with the hackintosh I had led me to buy a new MacBook last year (replacing my prior PowerBook, which was on its last legs), a decision I have not regretted one bit since.
My official recommendation is buy an inexpensive, used MacBook or Mac Mini running on Intel chips, then Snow Leopard if needed. Easier than trying to get a hackintosh running -- and if you factor in your time at a certain hourly rate, it may ultimately be cheaper. (It was for me -- and I bought a $1300 laptop!)