Min Apps, makers of Mint Nutrition, FallBall!, and Countdowns has organized a Promo Day for iPhone developers.
As a way to foster a sense of community among iPhone developers, they're giving away not only license codes to their own apps, but they've gotten several other iPhone developers to chip in promo codes as well. The only requirement to get the free promo codes? That you be an iPhone developer of some form. Codes are available here until they run out, so check it out!