Blogs, Portals/CMS, Customer Support, desks, forums, shopping carts, Image Galleries, Mailing Lists.

Blogs:
b2evolution (1.9.3) (website)
Nucleus (3.24) (website)
pMachine Free (2.3) (website)
WordPress (2.2.1) (website)
 

Portals/CMS:
Drupal (5.1) (website)
Geeklog (1.4.1) (website)
Joomla! (1.0.13) (website)
Mambo Open Source (4.6.2) (website)
PHP-Nuke (7.9) (website)
phpWCMS (1.1-RC4 Rev. A) (website)
phpWebSite (0.10.2) (website)
Post-Nuke (0.764) (visit site)
Siteframe (3.2.2) (website)
Typo3 (4.1.1) (website)
Xoops (2.0.16) (website)
 

Customer Support:
Crafty Syntax Live Help (2.14.4) (website)
Help Center Live (2.1.2) (website)
osTicket (1.3.1) (website)
PerlDesk (3.09 [Patched-1]) (Commercial, needs license) (website)
PHP Support Tickets (1.9) (website)
Support Logic Helpdesk (1.2) (website)
Support Services Manager (1.0b) (website)
 

Discussion Boards:
phpBB2 (2.0.22) (website)
SMF (1.1.3) (website)
 Yabb (website)
 

E-Commerce:
CubeCart (3.0.15) (website)
OS Commerce (2.2 MS2 (060817) + buySAFE) (website)
Zen Cart (1.3.7.1) (website)
 

FAQ:
FAQMasterFlex (1.51) (website)
 

Guestbooks:
ViPER Guestbook (X1.1) (website)
 

Hosting Billing:
AccountLab Plus (2.8 r11) (Commercial, needs license) (website)
phpCOIN (1.2.5) (website)

Image Galleries:
4images Gallery (1.7.4) (website)
Coppermine Photo Gallery (1.4.12) (website)
Gallery (2.2.2) (website)
 

Mailing List:
PHPlist (2.10.4) (website)
 

Polls and Surveys:
Advanced Poll (2.03) (website)
phpESP (1.8.2) (website)
PHPSurveyor (1.0) (website)
 

Project Management:
PHProjekt (5.2.2) (website)
dotProject (2.0.4) (website)
 

Site Builders:
Soholaunch Pro Edition (4.9.1 r10) (Commercial, needs license) (website)
Templates Express (website)
 

Wiki:
PhpWiki (1.2.10) (website)
TikiWiki (1.9.7) (website)