Windows: Go to the "windows" folder and download magicHack-windows.zip. Unzip into location of your choice and then double click on magicHack.exe. Instructions are in the zip archive.
Mac: Use git to clone the code repository. Your system probably already has python installed, but you need to download and install PyQt4. Then double click magicHack.py to use. Instructions are in the zip archive.
Linux: Same as Mac.
Developers: If you'd like to help develop make a ticket on this webpage indicating this, and provide a way to contact you.
IMPORTANT: magicHack only works in python 2.6. If you're using the Windows exe this doesn't matter for you because python 2.6 is bundled with the exe.