Free Software Directory
"We catalog useful free software that runs under free operating systems — particularly the GNU operating system and its GNU/Linux variants."
Linux App Finder
Guide to Linux programs by category; also lists popular Windows and Mac programs and suggests Linux alteratives.
Linux Replacements for Your Favorite Windows Apps
"Linux offers equivalents to many Windows applications that are often as good as--or even better than--the programs you're used to." This article discusses some of them.
Shutter
An excellent screenshot program for Linux.
6 Handy Sites To Learn New Ubuntu Tweaks & Tricks
"If you’re looking to expand your Ubuntu knowledge, have a burning question about some missing feature or are a newcomer to the world of Linux then these 5 sites are a great source of information."
The Best Of: Linux Software
"On this page, you will find the best 100 Linux applications for all your needs. We’ve taken the effort to categorize the apps and picked only those we believe to be the best ones and which will most likely be useful to you." A useful guide from Lifehacker.
Don't Fear the Penguin: A Newbie's Guide to Linux
"Linux has an undeserved reputation for being complex, cryptic, and difficult to use. With this simple guide, you can get started using Ubuntu Linux today."
Ubuntu Manual
"A comprehensive beginners guide for the Ubuntu operating system. ... The manual will help you become familiar with everyday tasks such as surfing the web, listening to music and scanning documents. With an emphasis on easy to follow instructions, it is suitable for all levels of experience."
Ultimate Linux Newbie Guide
"This guide can help both beginners and seasoned computer users alike learn all the important parts of choosing, using and installing Linux..."