I subscribe to several newsletters that About.com offers. The following information came in the pediatrics newsletter that I receive weekly.
According to the NICHCY, "as many as 1 out of every 5 people in the United States has a learning disability," but "there is no one sign that shows a person has a learning disability. Experts look for a noticeable difference between how well a child does in school and how well he or she could do, given his or her intelligence or ability. There are also certain clues that may mean a child has a learning disability."
Most of these clues "relate to elementary school tasks, because learning disabilities tend to be identified in elementary school. A child probably won't show all of these signs, or even most of them. However, if a child shows a number of these problems, then parents and the teacher should consider the possibility that the child has a learning disability."
This is just a sampling of the many newsletters they offer for free. To check out their complete list, go to About.com and search for what you are interested in. I bet you'll find a newsletter that matches your interests.