Here's a great way to acquire PP (Pin Points). The game rewards you with PP for time you don't play the game, up to one week (seven days). So, if you save your game and then play with your calendar on your DS, setting it ahead one week, you can get a week's worth of PP easily. Repeat this process as necessary, but keep in mind that you won't be rewarded for more than seven days' worth of Pin Points at a time, no matter how many days you set your DS ahead.