zzo38computer has released DS Basic, heres the info:
You can run BASIC on Nintendo DS. This program is based on a program called Integer Tiny Basic, I ported it to Nintendo DS and changed a bunch of stuff. You cannot edit programs on DS yet, but you can copy program to CF card and run.
Some things about DS BASIC:
You can press START is short for typing "RUN".
If you press SELECT it will list the .BAS files on the card to load.
There are no string variables, only numbers.
You can not do complex IF statements (as in A=0 OR B=3), but you can do something like IF A*(B-3)=0. Commands or editing (SAVE, NEW, LIST, etc.) don't work yet, but I hope to add them in next weekend.