S2 IT Consulting LLC has GasTracker + (iTunes Link) for the iPhone and iPod Touch in the iTunes App Store for FREE (regularly $1.99) for a limited time.

With Fuelly.com integration, GasTracker is the ultimate app for tracking your vehicle gas consumption and mileage. Whether you are an MPG fiend or if you’re just intrigued by your driving style, GasTracker is the app for you. Not only will GasTracker help you log how much gas you have spent, it will also show you how your driving pattern effects your overall MPG. You can track one car alone or all the cars in your garage. Add as many vehicles as you like!