Each console has their own SDK which are sold for a rather high price upon being launched.
I'd hate to say it, but if you wanna program for the DS, I would highly suggest programming for something a little simpler (and one that has an SDK that don't cost nearly as much anymore)..... like an NES.
If that goes well, then maybe step it up a notch. Maybe go for the SNES, or GBA. But if I were you, i would not go out and get an SDK for a console as advanced as that with little to no console programming experience under my belt.
The one and only,
~PlystirE~
[Edit]
Why is this in the 2D forum anyway?