The following sites provide a broad OVERVIEW of good information out there on the net.
Looking for specific topics?

Behavior Problems?
   TBI Teams
Tool Kit
Need a way to explain the important functions of the brain to upper elementary/middle school students?

The Brain: Our Nervous System by Seymour Simon is a picture book packed with great information about the function of the brain.  A warning to the squeamish- the book features photographs of the brain and spinal column.
CDC: Head's Up to School's:
Know Your Concussion ABC's
Returning to School After a Concussion:
A Fact Sheet for School Professionals