LOL, we have the same kid!
We got the gro clock.
Love love love it, only bummer is, you have to set it everynight.
Worked a charm here, we now have the absolute bliss of sleeping in till the grand ole time of 5.30 am
Do you think your DS is old enough to "get" the concept? I am not sure ours would have a year ago.
Still, get one anyways, you will prolly use it later on.