Mark has announced his project for the DS called InfrareDS, heres the info:
It's all in the name, with InfrareDS you can add an IrDA (Infrared) function to your Nintendo DS in just a few minutes!
Features
-Direct compatible to all firmware versions of the Nintendo DS (Nintendo DS Lite has not yet been tested)
-High speed data transmission to any other IrDA device (like PDA's, mobile-phones)
-Send pictures, sounds etc from Nintendo DS to PDA/Mobile Phone and backwards!