@7RAVI5: You think that kids 3-6 are buying the games themselves? Their parents buy them, and sometimes MAKE their kids play it!
@Try this Again: I think that this is a great idea! You will have a built-in market (parents). But, I think you need to tackle something more inovative than counting or ABCs, because, as Arkheii said, there are already better games for that area. Also, Math is WAY over flooded.
A few ideas that I have:
+The importance of 911, and when to call
+General safety around the house
+Dinosaurs (Kids love 'em!!)
+Marine life (Kids love 'em too!)
+Solar system
Maybe try your hand at one of these. You can also make one game, then make another in a series. If parents like one, they will be much more likely to get another if it is presented the same way.
P.S.- Don't listen to the nay-sayers. There is a large market for these games, especially with main stream games getting more and more for adults. Just remember, don't try to go against the already existing subjects! Inovate! Have fun and I hope this helps!