Fill a large pot of water about half full.  After the potatoes have been washed, cut them into 1/2 in cubes.  Put the potatoes in the water and bring it to a boil.  Start checking them after about 5 minutes.  They should be a little soft but not falling apart.  When the potatoes are finished cooked drain them in a colander and let them cool a little. 

While the potatoes are cooking make the dressing.  In a small bowl whisk together the oil, lemon juice, mustard, salt and pepper.  Chop up the herbs and mix them into the dressing. 

In a large bowl combine the cooked potatoes, dressing and the herbs.  Serve chilled or at room temperature.