FreeOS.com
Promotes free operating software. Contains articles, downloads and comparisons to various free OSs.
GeckOS/A65
6502 Multitasking operating system and implements some Unix-like features. Plus download, description and development.
Kernel.net
Aggregates news, reviews and tutorials about open source software and features original articles about Linux.
MacPorts
Provides MacOS X simple way to install open source software products, under BSD license.
R-Dir
Informative resource featuring websites devoted to R.
Tester Tools
Collection of free and commercial scripts and software.