Blogs:

• b2evolution
  A blog script featuring multiple blogs, categories/sub-categories, skins, search function, multiple languages, search engines friendly URLs. their website
• Nucleus
  A powerful blog script featuring multiple blogs, multiple authors, drafts and future posts, bookmarklets. their website
• pMachine Free
  This is a features limited version of pMachinePro. their website
• WordPress
  WordPress is a personal publishing tool with focus on aesthetics and featuring cross-blog tool, password protected posts, importing, typographical niceties, multiple authors, bookmarklets. their website
  

Portals/CMS:

• Drupal
  An advanced portal with collaborative book, search engines friendly URLs, online help, roles, full content search, site watching, threaded comments, version control, blogging, news aggregator. their website
• Geeklog
  A portal system with a wide range of modules. their website
• Mambo Open Source
  A professional level yet easy to use Content Management System featuring inline WYSIWYG content editors, newsfeeds, syndicated news, banners, mailing users, links manager, statistics, content archiving, date based content, 20 languages, modules and components. their website
• PHP-Nuke
  One of the most popular community-based portals with a big choice of modules and languages. (visit site)
• phpWCMS
  phpWCMS is perfect for professional, public and private users. It is very easy to learn and gives you the flexibility to separate layout and content. Lots of powerful but simple implemented features assists publishers and web developers too. their website
• phpWebSite
  Powerful Content Management System with announcements, menu manager, document manager, photo album, block maker, FAQ, web pages maker, polls, information categorizer, calendar, link manager, form generator. their website
• Post-Nuke
  Content Management System with focus on flexibility and security. A big variety of modules and blocks makes this CMS an allround tool. (visit site)
• Siteframe
  A straightforward content-management system designed for rapid deployment of community-based websites. Nice-looking templates, oriented toward document-sharing, clean interface. their website
• Typo3
  TYPO3 is a free Open Source content management system for enterprise purposes on the web and in intranets. It offers full flexibility and extendability while featuring an accomplished set of ready-made interfaces, functions and modules. their website
• Xoops
  A very popular advanced portal system. their website
  

Customer Support:

• Crafty Syntax Live Help
  A Live Help chat system featuring monitor your visitors, proactively open a chat session, multiple chat sessions, referer tracking, page view tracking, multiple operators, canned responses/images/URLs, multiple departments each with different icons, leave a message. their website
• Help Center Live
  Very powerful all-in-one help center including Live Help, Support Tickets and FAQ. Features include unlimited operators/departments, monitor visitors, initiate chat, collect visitor's information, track visitor's footprint, autosave chat transcripts, canned messages, leave a message, auto-assign tickets to operators, unlimited FAQ topics. their website
• osTicket
  A Support Tickets system featuring email piping, pop3 login, unlimited email addresses, admin/staff/user panels, avoid autoresponder loops, limit maximun tickets user can have opened, accept attachments and limit size, pager alerts for admin. their website
• PHP Support Tickets
  A simple, one-admin Support Tickets system featuring self-registering, emailing to admin, attachments. their website
• Support Logic Helpdesk
  A Support Tickets system featuring multiple email addresses, admin/staff/user panels, canned responses, HTML tags support, email limit on a per user/day basis, attachments. their website
• Support Services Manager
  SSM is a complete support desk, knowledge base management, and customer relations management solution. their website
  

Discussion Boards:

• phpBB2
  A widely-popular open-source bulletin-board package, works well, simple user interface and admin panel, clean look, scales well, and can easily be customized. their website
• SMF
  Elegant. Effective. Powerful. Free. SMF is all of the above. SMF is a next-generation community software package and is jam-packed with features, while at the same time having a minimal impact on resources. their website
  

E-Commerce:

• CubeCart
  An easy to use yet powerful shopping cart featuring unlimited categories and products, multiple payment gateways, downloadable products. The design is very easy to modify. their website
• OS Commerce
  A power-user shopping cart with a big variety of modules and support of almost every payment gateway. A big developers community is ready to offer custom solutions depending on your needs. their website
• Zen Cart
  Zen Cart truly is the art of e-commerce; a free, user-friendly, open source shopping cart system. The software is being developed by group of like-minded shop owners, programmers, designers, and consultants that think e-commerce could be and should be done differently. their website
  

FAQ:

• FAQMasterFlex
  Unlimited categories/questions/answers, with a web-based administration. their website

Guestbooks:

• ViPER Guestbook
  The ViPER Guestbook is a high end guestbook script that is versatile, reliable, very comfortable and easy to use. The perfect choice for the ambitious webmaster! their website
  

Image Galleries:

• 4images Gallery
  An Image Gallery system featuring unlimited categories/subcategories, web-based and FTP images upload, auto-thumbnails, comments, send a picture, rate a picture, random pictures, extensive administration panel. their website
• Coppermine Photo Gallery
  An Image Gallery system featuring categories and albums, thumbnails and intermediate size pics, search feature, new and random pictures, user management (private galleries, groups), user comments, e-cards feature, slideshow viewer. their website
• Gallery
  An Image Gallery system featuring albums within albums, thumbnailing specific picture area, captions, rotate, reorder pictures, album-based attributes, album mirroring. their website
  

Mailing List:

• PHPlist
  A powerful mailing list featuring multiple mailing lists and attachments. their website
  

Polls and Surveys:

• Advanced Poll
  A highly windows-inspired poll script. their website
• phpESP
  PhpESP is an effective, capable, web-based survey application that enables businesses to create complex and advanced surveys, view results in real time, and carry out advanced analysis. their website
• PHPSurveyor
  Develop, publish and collect responses to surveys. Display surveys as single questions, group by group or all in one page or use a dataentry system for administration of paper-based versions of the survey. PHP Surveyor can produce 'branching' surveys (set conditions on whether individual questions will display), can vary the look and feel of your survey through a templating system, and provide basic statistical analysis of survey results. their website
  

Project Management:

• dotProject
  Project Management featuring companies, projects, tasks (with Gantt charts), forums, files, calendar, contacts, tickets/helpdesk, language support, user/module permissions, themes. their website
• PHProjekt
  Project Management featuring optional group system, privileges, calendar, contacts, time card, projects, chat, forum, request tracker, mail client, files, notes, bookmarks, to-do list, reminder, voting, language support. their website

Site Builder

• Templates Express
  Fantastico De Luxe now comes with Templates Express, a series of static templates which you can install and immediatelly start building your website. These templates each sell to the public for $39, but are yours for FREE, if you are hosted with eFree2Net.com. - View Available Templates

Wiki:

• TikiWiki
  TikiWiki is designed to be an international, clean and extensible Content Management System and Groupware that can be used to create all sorts of web applications, sites, portals, intranets and extranets. TikiWiki also works great as a web-based collaboration tool. TikiWiki has a lot of native options and sections that you can enable/disable as you need them. their website
• PhpWiki
  PhpWiki is a web site where anyone can edit the pages through an HTML form. Linking is done automatically on the server side; all pages are stored in a database. their website
  

  Other Scripts:

• Dew-NewPHPLinks
  A Link Directory featuring categories, reviews, popular links, new links, links approval. their website
• Moodle
  A Course Management System designed to help educators create quality online courses. Available in currently 34 languages, featuring WYSIWYG HTML Editor, teacher has full control over all settings for a course, flexible array of course activities (Forums, Journals, Quizzes, Resources, Choices, Surveys, Assignments, Chats, Workshops), user logging and tracking, mail integration and much more. their website
• Noah’s Classifieds
  A classifieds system featuring categories and subcategories in unlimited depth, image upload for categories and classifieds, variable fields per categories, customizable email notifications, locking categories, classifieds approval, auto-thumbnail generation, classifieds management by user, send classified to a friend. their website
• Open-Realty
  Real Estate listing system featuring attachments, flexible search, template system, Yahoo Maps interface. their website
• phpAdsNew
  A highly professional complete ad server featuring different types of ads, display based on keywords, zones, hour of the day, day of the week, extensive statistics, client statistics. their website
• PHPauction
  The GPL version of PHPauction featuring email notification of bids, attachments, reserve price, minimum bids, standard and dutch auctions, bid history, send auction to a friend, highest bids, auctions ending soon. their website
• phpCOIN
  A full billing/invoicing application, perfect for webhosting resellers. You can install only one instance of phpCOIN! their website
• phpFormGenerator
  A form generator featuring up to 100 form fields, all kind of input fields incl. file upload, customizable fields attributes, send submitted data to an email address or store them in a database, admin panel. their website
• WebCalendar
  A very powerful webcalendar featuring private and public calendars. their website