I used to use amSTATZ but two other options I have really liked even better was mindbody.com and http://www.fitsw.com/. Mindbody was very nice and professionally done – the only downside was that it’s pricey. FitSW seems more tailored for individual trainers / smaller gyms because its Free – just not quite as polished as Mindbody. Both Fitsw and mindbody have excellent ways to track progress on your client’s fitness and they both do a great job at recording workouts and diets. They both do an outstanding job of letting me manage all my client’s info in one location.