I'll be using
www.fuelly.com to track my mileage when I pick up my car next week. It appears I'm the only AH3 owner tracking at this time. I've never done it before, but figured it might be fun.
I encourage all other AH3 owners to sign up. You input the gas information at the pump on your smart phone. It's basically like an app, but you use the mobile browser + sign in, to input your data. I use an iPhone, but I'm sure it's the same for Android.