Wall Street Journal 03/16/11
"Waze: Avoiding traffic is one of the best ways to save on gas. Waze uses real-time traffic updates from other users to help you steer clear of traffic snarls. Users report traffic jams, accidents, police traps,
road and road hazards. Similar to check-in sites and apps, Waze offers badges and discounts for reporting. It's free, and compatible with iPhone iOS 3.0 or later."