The Arduino Prototyping Shield makes it easy for you to design custom circuits. You can solder parts to the prototyping area to create your project, or use it with a small solderless breadboard (not included) to quickly test circuit ideas without having to solder. It's got extra connections for all of the Arduino I/O pins, and it's got space to mount through-hole and surface mount integrated circuits. It's a convenient way to make your custom circuit and Arduino into a single module.
A wide prototyping area with some extra features:
EAGLE files: arduino_ProtoShield_Rev3.zip
The Proto Shield bring the power from the Arduino standard 5V and GND pins to the two power bus rows placed between the Through Hole package footprint, which can be used for powering the DIP sockets, or for power and ground rows.
The ICSP connector available on the shield hove his connections made directly to the SPI pins.
For more information about the SPI communication see the SPI library.
The maximum length and width of the Proto Shield PCB are 2.7 and 2.1 inches respectively. Three screw holes allow the shield to be attached to a surface or case. Note that the distance between digital pins 7 and 8 is 160 mil (0.16"), not an even multiple of the 100 mil spacing of the other pins.