Thanks to Elizabeth Thacker at Plum Grove Strings, I was made aware of this article in the LA Times:
The article outlines a study that was recently done which related music lessons to brain function. Much research has been done showing the link between music and mental health, but this study went one step further. Students that took lessons even years earlier showed better brain function than their peers.
Music lessons for children not only benefit them today, but will help them for years to come.
Another article in the LA Times discusses how actually participating in music (singing or playing an instrument) has much greater impact on the mind than passively listening. Instead of putting classical music on your child's ipod, try putting your child into music lessons.
These are a couple of articles that music teachers could reference when talking with parents or prospective students.