Shozam requires Windows to run on a computer. If you have a modern Mac computer, you can run Shozam on it if you also install Windows on your Mac. You can do this using Apple Bootcamp, Parallels Desktop or VMWare Fusion.

Apple Bootcamp
http://www.apple.com/macosx/features/bootcamp.html

Parallels Desktop
http://www.parallels.com/products/desktop/

VMWare Fusion
http://www.vmware.com/products/fusion/

For more about how you can run PC programs on a Mac, please see the following related articles:

http://ptech.allthingsd.com/20081001/one-way-to-turn-a-mac-into-a-pc-just-got-better/

http://www.pcmag.com/article2/0,2817,2344661,00.asp