Snow Transformation Pack will transform your entire user interface to Mac OS X Snow Leopard, including Snow Leopard Welcome Screen, Visual Style, Icons, Wallpapers, Sounds, Dock and much more.
This pack is really worth a try. If you are a Mac user and trying to get familiar with Windows 7 or Vista then give it a shot. It will change almost everything from logon screen to visual style and make it look like Mac OS. Do not forget to disable UAC before installing this pack. Also create a system restore point before doing this so that if anything goes wrong you can easily revert all the changes and get back to your old Windows 7 look.
This is one of the best pack I have seen for Windows 7 and it contains everything that you will require to make your Windows 7 look like Snow Leopard. The pack is specifically created for 32-bit systems but will work on 64-bit systems also.
A readme file is included in the pack. Just follow the instructions given there to turn your Windows 7 into Snow Leopard.