This isn't really school related, but it's important and useful, so I decided to share it here. This would also be good to share with students in a health or nutrition class.
There is now an iPhone App you can use when you're in the produce department, trying to remember if you should buy organic peaches or not (you should).
According to the EWG, you can reduce your pesticide exposure by up to 80% if you buy organic versions of the Dirty Dozen.
Environmental Working Group
Dirty Dozen iPhone App
No iPhone? Download a pdf form of the guide.