ForeFlight

If you're a commercial or general aviation pilot, you know it's crucial to get the airport, aircraft, weather, and routing information you need to plan and execute a flight before you reach the airport. With ForeFlight for iPhone, you can get airport directories, flight times, and weather information right on your phone. This helpful information for pilots requires a subscription which costs $7.50 per month or $75 per year.
iPhone Link:
http://iphone.foreflight.com/
Web site link
http://foreflight.com