Nintendo DS development

My best guess is that it acts simalr to a mouse. When you touch the screen, the coordinates at where you touched act like a cursor's coordinates. But this is just a guess.

Super-Secret DS Resource Thread

I seem to remember (from the very start of DS dev, before it turned from "Holy hell, what is in this thing?" to "hay wy cant i get snes emulator for this thing LOL") that pressing the screen will issue an interrupt, and somewhere in the interrupt data is the X,Y of the screen location you poked. That's about it.

You should definitely learn C before you try anything with the homebrew DS kits, though.

Have a read of : http://www.double.co.nz/nintendo_ds/nds_develop3.html