J2ME or Java 2 Mobile Edition would certainly be cool on the Nintendo DS. It was made to run Midlets (Low resource java applications) on low resource systems like cell phones and so on and theres literally thousands of games and applications out there written for the J2ME. I beleve it should be possible and the Nintendo DS has more then enough resources to handle J2ME.
The source for J2ME is available under the GPL I believe.
The source for J2ME is available under the GPL I believe.











