GasBuddy is a free app for most platforms that compiles gas prices using tips from users across the country. It sorts stations by price or distance.
iGasUp gets its prices from the Oil Price Information Service, which generates real-time data using credit card transactions at more than 100,000 fueling stations. This iPhone-only app maps the 10 nearest stations and sorts them by price.
Cheap Gas! is an iPhone, iPod Touch, and iPad app that maps routes to gas stations and uses GasBuddy’s price data.
Poynt provides a lot more than local gas prices. This free app also gives you distances and directions to movies, restaurants, and more. (BlackBerry, iPhone, Android, Windows Phone 7)
GasBook, another iPhone-only app, offers multiple ways to sort gas-station data.
Source: The Hartford Courant