How can I create a dual boot with Mac on a Windows machine?

31 Mar 2012
Windows 7 (64-bit)
Firefox 11
31 Mar 2012 | Windows 7 (64-bit) | Firefox 11

So, recently I wanted to make a dual-boot on my PC for both Windows and Mac. But before I start doing that using the MakeUseOf tutorial I have some questions:

1. I saw that it was possible to make a dual-boot. How much GB does the Mac system require? And how should I do the dual-boot?
2. Is it possible to do this with a hacked copy of Mac OSX, e.g. or somthing?
3. Can this be done with a 16 GB usb-stick as well??