its quite simple really
not sure about exact parts - I suspect that it doesn't matter that much - its quite a simple design. My best guess would be 1Ks for the resistors and 1uF for the caps.
the component marked 'M1' is an ammeter.
Bassically, when you lie, because of various factors, you skin resistance goes down. So you place the electrodes on someones skin, and if they lie, the resistance accross the electrodes will change, and the ammount of current flowing through the ammeter will also change, and the needle will move dramatically (hopefully). This movement shows that they are lying. The variable resistor is to adjust the sensitivity, and some people may have different natural resistances, and some adjustment may be needed.
Does that help at all?
Tim