http://www.katamibar.com/order.php
I got the full system (7 DVD's, 2 bars, stability ball & pump) in January and have been addicted ever since. The workouts are only 35 mins long and got me back into morning exercise. The stability ball workout is the only one that is longer - 1 hour - and I do that one on my days off.
This guy is good. His emphasis is on doing a few reps correctly rather than execising forever while cheating your body of the rewards due to improper form. After doing his workout I definately feel my stomach muscles (upper, lower and obliques) all day long and I love it. I'm accustomed to doing step aerobics for 45 minutes until i'm sucking wind so sometimes I do the aerobic part of his workouts twice (just in case).
All in all, great system that got me back into regular workouts!