There's not much difference between the GBA and DS when it comes to Final Fantasy. For one thing, the second screen is barely used in FF3, and the touch pad controls aren't used at all. Secondly, if you still insist on playing a Final Fantasy game on your DS, just put any of the 3 GBA remakes into your DS and play it off of there, you won't notice the difference. (Actually, the only difference there is that the 3 games on the GBA are far superior to FF3, so in which case, just buy them instead.)