http://forum.facepunchstudios.com - Garry's Mod Forums
http://boards.pocketheaven.com/index.php
http://forum.gbadev.org/index.php

Nintendo DS Info and Howtos
http://tobw.net/dswiki/index.php?title=How_to_run_code
http://www.darkain.com/nintendo_ds/nifi.php
http://drunkencoders.com/
http://www.bottledlight.com/ds/
http://wiki.pocketheaven.com/
http://www.natrium42.com/
http://darkfader.net/ds/
http://www.ndshb.com/
http://www.dspassme.com/FlashMe.shtml
http://ds.gcdev.com/dsfirmware/
http://www.double.co.nz/nintendo_ds/index.html

Notable homebrew programs
http://www.dslinux.org/index.php?act=home
http://nitrotracker.tobw.net
http://pineight.com

Nintendo WFC
http://www.nintendowifi.com/gaminghub/Gamehub.jsp

UNIX/Linux and OSS
http://www.gnu.org/software/gnash/
http://gplflash.sourceforge.net

Mirror sites 
http://psx00.com
http://diggdown.net