"MacDrive" from MediaFour does this flawlessly. This product, which installs on a Windows computer, allows you to mount, read from, write to, and exchange content stored on Macintosh formated drives.
http://www.mediafour.com/products/macdrive6
I use this at work to mount student media stored on their Mac drives to a PC that's setup to uprez their content to HD. I also use their "XPlay2" software to mount my iPod to my PC at home.
It does what it says it does and it does it well.
PowerBook G3 Lombard Mac OS X (10.3.8)