Anyone with a DSi needs to log onto the shop and download it. It's a free app that lets you make your own frame-by-frame animations. It has an adjustable lightbox (to show prior frames through the current page), multiple brush textures and sizes, two animation layers per frame variable animation speed, and some pretty powerful cut and paste tools in addition to basic sound mixing support (including imported sounds from DSi Sound). It only has black, blue, and red as far as colors, though.
The biggest downside to the software is that drawing on the DSi's screen is kind of awkward. A textured screen protector would help make it more paper-like to draw on, but unfortunately those also destroy image quality. Still, I've been having fun making some gory cartoons of people getting sawed to pieces and tanks exploding and crap like that.
One of the neatest features of the program is that it allows you to upload your animations to flipnote.hatena.com for others to view. Some of them are really, really good.
