This is a great article about a journalist, Katherine Ellison, who herself was undiagnosed with ADD, and her struggles and success in parenting her ADD son. She wrote a book about her experiences and how she chose mindful parenting over meds.
This is not a proven technique by any means. Here is the full article by Katherine Ellison of the New York Times, Neurofeedback Gains Popularity and Lab Attention. Here are some key paragraphs: