Here are some of the common signs of learning disabilities for preschoolers:
It would certainly be to your advantage to have your child evaluated. You have a right under federal law to request a free evaluation from your local school system. If you have any trouble getting started or if you want someone to help walk you through the system, contact the Coordinated Campaign for Learning Disabilities (www.aboutld.org) at 1-888-GR8-MIND. They will help you to find a parent support group in your community where you can get more assistance. They can also send you free information about learning disabilities, including their booklet Learning Disabilities: Information, Strategies, Resources. I'd also read Susan Hall and Louisa Moats' book, Straight Talk About Reading: How Parents Can Make a Difference During the Early Years.
The best reason for getting an evaluation early is that research shows that if you identify and give appropriate supports to a child in kindergarten or first grade, there's a 90 percent chance that he will become at least an average reader. If you wait until much later, the odds of improving his skills sufficiently become much less.