Linux:

http://www.linuxnarede.com.br/forum
http://focalinux.cipsga.org.br/gol.html
http://www.vivaolinux.com.br
http://www.slacklife.com.br

Regex:

http://www.aurelio.net
http://guia-er.sourceforge.net
http://www.regexp.com.br
http://www.regexpal.com

Unix:

http://www.rau-tu.unicamp.br/freebsd
http://www.primeirospassos.org

WordPress:

Documentation codex.wordpress.org
Plugins wordpress.org/extend/plugins
Suggest Ideas wordpress.org/extend/ideas
Support Forum wordpress.org/support
Themes wordpress.org/extend/themes
WordPress Blog wordpress.org/development
WordPress Planet planet.wordpress.org