@kelbot
#GBATemp is overall a decent resource for info, though I must admit I haven't really looked into #NDS #homebrew for quite some time.
#DSorganize is a nice #PDA-like organiser util with a file browser (which will play audio files), todo list, calendar, day planner, address list, scribble pad, and even web browser and IRC modules, and a homebrew database.
There are also various emulators, though IIRC the lower resolution compared to a TV, means you'll miss some lines on e.g. #SNES games.