The Sensor Shield v.2 allows you to hook up the TinkerKit SENSORS and ACTUATORS directly to the Arduino, without the use of the breadboard.
It has 12 standard TinkeKit 3pin connectors. The 6 labeled I0 through I5 are Analog Inputs. The ones labeled O0 through O5 are Analog Outputs connected to the PWM capable outputs of the Arduino Board (it is possible to change these to Digital Inputs, in which case they will report either HIGH or LOW, but nothing in between).
On a Standard Arduino DuemilaNove board the pins are:
Pin 11 on the Arduino is O0 on the shield.
Pin 10 on the Arduino is O1 on the shield.
Pin 9 on the Arduino is O2 on the shield.
Pin 6 on the Arduino is O3 on the shield.
Pin 5 on the Arduino is O4 on the shield.
Pin 3 on the Arduino is O5 on the shield.