ima2raw - download
This tool will remove the header and index blocks from a 4bit mono ima-adpcm wav file(I didn't try stereo), making it the right format to be fed directly to the ds's sound hardware. It works for adpcm's created with windows soundrecorder and with cdex, but failed with an adpcm made with sox, I didn't bother to look into it.
I borrowed code heavily from the DS ScummVM source code, and included the source in the zip. It's compiled for dos but it should be fairly simple to compile for any platform.
Updated July 23rd, 2006 to fix a bug that put a chunk of bad wav data at the end of raw files.


BMP Splitter - details
This is a Windows tool I wrote to export sprites and maps into a format useful for the gba/nds.
Updated April 23rd, 2006 to a much more bug free version with a few extra features for sprite export and for high color bitmap mode.


Server List Sample - download
A simple Game Server Browser for the DS, it sends list/add/remove requests to the master server. The only files that need to be added to an existing wifi project are ServerList.cpp and .h.


Box2d demo/port running on ds - download zip - download rar
I compiled Erin Catto's Box2D engine to get it up and running the the ds. Not much to look at, really. Go check out Erin's weblog if you find physics programming interesting.