I came across a recent post via msn health and fitness which mentions "fatty-acid supplementation (800 mg per day) for three months significantly improved reading, spelling and behavior in children with attention disorders. Researchers at the University of Pittsburgh Medical Center reported a correlation between higher blood levels of omega-3 fats and fewer impulsive behaviors."
The article also says that although the science is new,experts say a daily fish-oil supplement may improve mental focus and probably will provide cardiovascular benefits.
Personally I've been taking fish oil ever since I heard Dr. Jose Antonio PhD, noted leader in performance sports nutrition, speak about it's benefits.