Operating Systems - Linux
http://www.linux.com/
Linux.com site provide a unique combination of news, original articles, downloadable resources, and community forums to help IT managers, development professionals, and end-users make critical decisions about information technology products and services.
http://www.linuxjournal.com/
Since 1994: The Original Monthly Magazine of the Linux Community.
http://www.li.org/
Linux International, also known as LI, is a world-wide non-profit association of end users who are dedicated to furthering the acceptance and use of Free and Open Source Software (FOSS).
http://www.linuxtoday.com/
News, forum, related to Open Source software and community. Many items daily. Updates daily/hourly.
http://www.linux-mag.com/
Linux Magazine Online contains over 1,000 new and reprinted articles about Linux desktops, programming, system administration, and hardware.