Loopy and FluBBa have released a new version of nesDS. This program will convert .nes files to either .ds.gba or .nds files, allowing you to easily play NES games on your Nintendo DS. To build an .nds file, you will need ndstool.exe which can be found [here]. Usage:

– Touch the screen to bring up the ingame menu.
– L,R buttons are rewind / fast forward controls.
– X,A buttons are autofire for Y,B.
– Saving is still broken, but SRAM (.sav) files will be loaded if found.