The 3 hardware items you need to do homebrew DS development are:
I’ve got a DS Lite so I picked up a combo package that include a Super Key, a SuperCard MicroSD reader and a 1GB micro SD memory flash card. — Doug Daniels 2007/01/18 20:55
I've got no tutorials yet, but once I get a chance to play around with this stuff again I'll post some OpenGL tutorials. For now just check out the resources (feel free to contribute any more links that you find). — Doug Daniels 2007/01/18 20:48
Here are some links to get more info on DS Homebrew development: