The answer depends on whether you qualify for the American Opportunity credit, The Hope credit, or the Lifetime Learning credit. In any one tax year you can only claim one of these credits, and then only if your adjusted gross income is below the max threshold for that credit. Also your son must be your dependent for you to claim the credit. Assuming you qualify, the credit may be as much as $2500. Details are in Pub 970, here:

http://www.irs.gov/pub/irs-pdf/p970.pdf