Google Code
- directory of in-development open source projects
- http://code.google.com/hosting/

UNESCO Free Software Portal
- A central directory of Open Source software, designed for a worldwide audience. Includes the latest industry news.
- http://www.unesco.org/cgi-bin/webworld/portal_freesoftware/cgi/page.cgi?d=1

Ohloh
- Provides comprehensive metrics and analysis on thousands of open source projects and contributors.
- http://www.ohloh.net

GNU/UNESCO Free Software Directory
- Lists free software packages organized and searchable by category.
- http://directory.fsf.org/

Open Source Software in C# (C-Sharp)
- Directory of open source software focused in C#.
- http://csharp-source.net/

Enterprise Open Source List
- A human edited directory of professional Open Source Software intended for the IT community.
- http://www.eoslist.com

Open Source Alternative
- Helps you find open source alternatives to commercial software.
- http://www.osalt.com/

NASA Open Source Software
- Lists open source projects that could be essential to NASA missions. Help NASA with development of their projects - or simple enjoy them.
- http://opensource.arc.nasa.gov/

Open Source Scripts
- Directory of scripts in various languages (Perl, PHP, JavaScript, ...).
- http://www.opensourcescripts.com/

IBM DeveloperWorks: Open Source
- IBM's open source site includes articles, tutorials and a list of open source projects.
- http://www.ibm.com/developerworks/opensource

OS Reviews
- Website publishing reviews of free and open source software.
- http://www.osreviews.net

OSZone
- Listing companies and projects with individual reviews. Includes profile, blog related technologies and associated links.
- http://oszone.org/

Opensource Info
- A listing of distributions, applications and websites including their features. Includes forums, links and the latest news.
- http://www.opensourceinfo.org/

My Open Source
- A guide to Open Source software for the Windows platform. Lists most popular downloads and offers a review of each product.
- http://www.myopensource.org/

BBC Open Source
- Provides information about and links to BBC open source projects.
- http://www.bbc.co.uk/opensource/

Goodie Domain Service
- Software, shareware and lots of useful hints to related information. Includes directory, search and associated links.
- http://gd.tuwien.ac.at/

Java Open Source Software
- A directory of open source software focused on java.
- http://java-source.net

Open-Source Directory
- Directory of open-source and just working programs.
- http://www.osdir.com/

Freshmeat
- Unix and related software in all stages of development. Daily release announcements. Not restricted to open-source software.
- http://freshmeat.net