Purely for fun and to get a geeky sense of achievement when it works, but have a look at
http://www.theregister.co.uk/2008/10/20/macosx_on_a_pc/
It does work - the guy used AMD and had trouble when software update updated, but the last security update on Intel proved no probs for me when I put it through yesterday. Great fun!!
I particularly like the comments on the screens...
"
The Kalyway license page. Its not quite clear what we're agreeing to, as this is pirated software. But hey, at least it looks official."