This shield plugs on top of my boarduino and allows it to copy its bootloader to the blank atmega chip on the sheild. This makes it extremely easy from me to make new arduinos in seconds with out spending more money on a avr programmer.
All you have to do is plug the shield on, plug 5volts into the boarduino, then push the button on the shield. the led blinks green a few seconds then stops, if a error occurs then the led will turn red and the buzzer will sound.
Now if you used the old methods it would take several minutes this only takes 2 seconds.