You'll prob get more replies and good feedback if you posted this in the Training Board.
Shin splints can sometimes occur because of a muscle imbalance between your calves and your anterior tibialis ("shin muscle"). Your calves are probably a lot stronger than your ant. tib. - so try working on getting rid of that imbalance to see if that helps at all.
Try walking around on your heels (toes in the air, you'll look funny, but you'll *really* feel your ant tib). Do like 30 seconds on heels, 30 seconds regular, keep repeating. I always do a couple before sprints to make sure everything is warm.
Also, could be your shoes. How old are they? (worn out?) Are they *running* shoes? (you shouldn't run in cross trainers)