I've found the charts on the Latitudes site really helpful for my ADD daughter as far as completing work after school. They help me not nag--it just goes on the chart. We keep the rewards very simple and not pricey.
I think they are a little tricky to find--you have to go to their website Learning disab. or maybe adhd also (?) and look for the frog picture. click on it and it takes you to the charts. I used to make my own. my daughter likes these better. i hope they will be putting more up.