I recently bought this 6V 500mA polulu regulator
and use it to feed an arduino from a Lipo 4S (16.8 V max) in a quadcopter.
At the end of your page there is the recommandation:
"If you are connecting more than 20 V or your power leads or supply has high inductance, we recommend soldering a 33 μF or larger electrolytic capacitor close to the regulator between VIN and GND. The capacitor should be rated for at least 50 V."
Though my Voltage is lower than 20V, i'm still wondering if with ~ 15cm leads (typical breadboard wires) it would be more cautious to add the electrolytic capacitor in parallel with the polulu regulator ... ?