Linux: Online Resources
If there is one Linux community you join ... this is the one. Linuxquestions.org currently has over 400,000 registered users and 3.5+ million posts making it a very active community with a wealth of information. Here you will find Linux Tutorials, Distro Reviews, Book Reviews, a popular HCL (Hardware Compatibility List), and the bulk of the site ... the forums. I can't tell you how many times in the past I have turned to the members of this site for an answer to a question I've had about one of my numerous Linux installs. I have found the community to be polite (most of them), knowledgeable, and in most cases eager to help. Currently I find myself answering more questions for the members than I ask but on those occasions when I am stumped with a Linux issue I still turn to the members of Linuxquestions.org.
The place to be for Ubuntu Linux related issues. This is another very active site and a great community. Overall the members are knowledgeable and eager to help, although the odd flame war has been known to break out here. One thing worth mentioning about the Ubuntu Forums is that it is geared specifically towards Ubuntu Linux users but contains a wealth of information that any Linux user can make use of. Ubuntu users have also been known to, on occasion, help people with issues specific to other distributions.
Another fairly active Linux forum. I do not have nearly as much experience with this forum but I keep it bookmarked should LinuxQuestions.org and Ubuntu Forums fail me! Definitely worth a look.
FOSSwire Ubuntu Reference
Speaks for itself. A great Ubuntu Reference cheat sheet. Print it and keep it handy as you learn Ubuntu.
FOSSwire Installing Software on Ubuntu
This cheat sheet focuses on the installation of software in Ubuntu. Another one worth keeping handy as you learn Ubuntu.
FOSSwire Unix/Linux Command Reference
The best basic command line reference I've been able to find. Does not go into great detail or cover the more obscure commands but every Linux Beginner should start by learning the commands on this cheat sheet.
HowtoForge - Linux Howtos and Tutorials
An extensive list of Linux How-to's and Tutorials. Most are very well written and contain a limited amount of outdated or false information. As a Linux Beginner you will benefit greatly from spending some free time going through these tutorials.
Online Man Pages
Comprehensive list of Commands, Subroutines, Files & Formats, Games, Macros and Maintenance.
Some hate Slashdot while some love it. No matter what you think of Slashdot in general I have found many interesting stories and tutorials in the Linux section. Bookmark it and visit it daily ... you never know what you'll learn.
Lastly, the best Online Resource for Linux Beginners. All the information you will ever need on Linux is just a search away.