Just in time for those new year resolutions, PushupFu is a new paid-for iPhone/iPod Touch application [App store link] designed to get you fit, via press-ups. There are now a lot of fitness apps available for the iPhone. Current leader WeightBot lets you weigh yourself daily. Others like iPump let you email your progress to virtual Gym buddies. However, there are no native apps I know of which have turned exercises into a Wii Fit-style game where you can pit yourself against others on the same service – exactly what PushupFu does – by using the iPhone’s accelerometer to verify that you actually did the exercise.