As with most subversion repositories, there are 3 directories in the main level, branches, tags and trunk.

The trunk line has a few different directories:
ds-lib-gambit
	Scheme-C interface libraries to libnds, wifilib, libfat and palib
gambc-4.0b20-nds
	Original NDS gambit port
gsi
	Gambit Scheme Interpreter for NDS
thee-stack
	A PDA/Organization/Flashcard program I am working on.  Serves as an example of how to make a scheme NDS program.