I’m lazy. Well, at least when it comes to getting my butt out of my chair and doing anything other than work. Chances are, if you’re reading this, then this same description fits you. So when I first heard about the ethos behind FitFu, it seemed like something I could get behind.

The idea is that getting some kind of exercise every day shouldn’t take a serious commitment. Instead of joining a gym or playing a workout DVD for 30 minutes each day, FitFu gives you a whistle to remind you to get up and get active for about 5 minutes, twice daily.

I first wrote about FitFu a few months ago, before I even had my own iPhone on which I could run it. I was able to test it with a loaner device and, as soon as I had to give it back, I started missing the ability to use the app. Since FitFu works by measuring your movement, you’ll need the latest generation of the iPod touch or an iPhone 4 in order to play its games.

I did have a couple of gripes with the versions previous to the latest. Your first few days with FitFu can get a bit monotonous, with only having squats, push-ups and crunches. You would unlock more as time went on (and that desire helps to drive you forward),  but even those felt a bit lacking. Now there are 4 new exercises to keep things interesting.

In-app purchases have also been eliminated from FitFu in version 1.7. The app runs $4.99, but that’s all you’ll ever have to pay. You can also now add your friends on FitFu to a group of favorites.

That social aspect of FitFu is another section that makes it truly stand out. A gentle reminder from a friend is sometimes all that it takes to get you off of your butt, and that’s hard to accomplish when you’re sitting around in an office or on your couch, hacking away. FitFu’s social system awards points for your activity and your friends can earn points by poking you to get off of your butt.

In short, it’s still my favorite exercise app for the iPhone, only now it’s better. So get downloading and let us know your thoughts in the comments.