^ As alvine said above. But if you still need to format Fat32 this should still work http://hints.macworld.com/article.php?story=20040724110933265
it was done for Panther but should still work with Mountain Lion. If the files you need to share between Windows and OS X are 4gb or smaller then there should be no problems but just remember fdisk is not forgiving so if you make a mistake and choose the wrong drive it is gone!
I have not tested it on my Hackintosh 10.8.2 as I use Paragon on my Hackintosh and Windows 8. For me it is the best solution for both OS's.