Last question so far: Do you know how to incorporate the PIR sensor? Do I need a sensor shield? (i'm working with 5 PIR sensors, each has to work seperately from the others)
I just used one of those today for writing up in my Arduino-Info Wiki (http://arduino-info.wikispaces.com/)
Take a look here and you will see how I connected them:
See the discussion here: http://arduino-info.wikispaces.com/Brick-Pushbuttons%26OtherSwitches#Motion
A Sensor Shield http://arduino-info.wikispaces.com/SensorShield just makes it easy to connect lots of different things to Arduino without the wiring getting out of control.. With cables that plug in etc.. like on this page: http://arduino-info.wikispaces.com/BrickStarterSet