Golfr

This super simple yet robust iPhone app from the guys at Seattle Ubermind has all the deets for 15,000 golf courses across the US (directions, contact info, etc.), plus the distance/par, course ratings and topography for every hole, and even lets you compare greens fees during standard, weekday or twilight, a notably cheap time to play despite having to contend with all those 14-year-old girls.