I just tried out a homebrew DS app last night called Phidias. It's a bit rough around the edges, but it's pretty fun to play around with. It's no replacement for a sketchbook, but it's nice to be able to draw without carrying around extra tools and such. It saves images out in .bmp format. In the current release, there's no way to load images to continue working on them later, but I've heard there might be in a future release.
Drawing at that small a size was a little annoying at first, but after awhile it got to be pretty fun.
Here's the main page:
http://www.sivullinen.fi/nds/projects.ph...amp;ucat=2&
Replies
It works pretty damn well actually. Of course you cant get very detailed, but when I have an amazing idea out of nowhere its nice to bust it out and sketch it down.