Below is a link collection for GNU/Linux.
- The Linux Kernel Archives
- The GNU Operating System
- Linux.com | The source for Linux information
- DistroWatch.com: Put the fun back into computing. Use Linux, BSD.
- Debian -- The Universal Operating System
- Ubuntu homepage | Ubuntu
- Linux Mint - Main Page
- redhat.com | The World's Open Source Leader
- Fedora Project
- The Slackware Linux Project
- Arch Linux
- Puppy Linux
Free and open source software (freedom, cost, patents, copyright/left and licensees)
- Welcome — Free Software Foundation — working together for free software
- Debian Social Contract and the Debian Free Software Guidelines (DFSG)
- Mission | Open Source Initiative
- Open Invention Network
- Linux Defenders
Desktop Enviroments and Window Managers
- GNOME: The Free Software Desktop Project
- KDE - Experience Freedom!
- LXDE.org | Lightweight X11 Desktop Environment
- Xfce Desktop Environment
- Openbox - Main Page
- Enlightenment - Beauty at your fingertips
- awesome window manager
It's free to download most GNU/Linux distrubutions and easy to burn them on CDs or DVDs yourself, but you can also buy them at quite low price.