Mac Theme for Windows 7
If you’re using a Windows 7 machine, why not make it look like Mac OS X? This task is made very easy with a theme/skin set called the Snow Transformation Pack, it turns your Windows 7 theme into a very convincing near complete Mac OS X interface including icons, wallpapers, the Dock, sounds, dialogue boxes, login screen, window skin, and more.
The Snow Transformation pack is freeware and available to download here
Of course if you’re this obsessed with Mac OS, you should probably just buy a Mac and save yourself from the burden of Windows 7 and trying to skin it to look like a Mac, right?