When you save and turn off the Nintendo DS, you will gain PP points for the pins you have on. You can use this to your advantage by changing the system date. Save your game, turn off the Nintendo DS, turn it back on, go to the date setting, then set it forward by seven days. The Nintendo DS will turn itself off after you are done. Turn it back on, and load your game. You should gain PP points for seven days. Repeat this as many times as desired. Once done, save the game, and change the date back to the correct value.