Fantastico De Luxe is an amazing CPanel/PHP based Web application. It integrates with CPanel and gives your clients the ability to automagically install following Open Source Applications:

Blogs:
b2 (0.6.1)
b2evolution (0.8.6.2)
Nucleus (2.0)
pMachine Free (2.3)
WordPress (1.0.1)

Portals/CMS:
Drupal (4.3.2)
Geeklog (1.3.8-1sr4)
Mambo Open Source (4.5(1.0.3))
PHP-Nuke (7.0) (visit site)
phpWCMS (1.1-RC2)
phpWebSite (0.9.3-2 english)
Post-Nuke (0.7.2.6-1) (visit site)
Siteframe (3.1.2)
Xoops (2.0.5.2)

Customer Support:
Crafty Syntax Live Help (2.7)
Help Center Live (1.2.2)
osTicket (1.2.5)
PHP Support Tickets (1.7)
Support Logic Helpdesk (1.1)
Support Services Manager (1.0b)

Discussion Boards:
Invision Board (1.3)
phpBB2 (2.0.7)
YaBBSE (1.5.5c)

E-Commerce:
CubeCart (2.0.1)
OS Commerce (2.2 MS2)

FAQ:
FAQMasterFlex (1.0)

Image Galleries:
4images Gallery (1.7)
Coppermine Photo Gallery (1.2.1)
Gallery (1.4.2)

Mailing List:
PHPlist (2.7.2)

Polls and Surveys:
Advanced Poll (2.03)
phpESP (1.6.1)
PHPSurveyor (0.97)

Project Management:
PHProjekt (4.1.1)
dotProject (1.0.2)

Wiki:
PhpWiki (1.2)
TikiWiki (1.8)

Other Scripts:
Moodle (1.1.1)
Noah’s Classifieds (1.3)
Open-Realty (1.1.4)
phpAdsNew (2.0)
PHPauction (2.1)
phpCOIN (1.2.0)
phpFormGenerator (2.06)
phpLinks (2.1.2)
WebCalendar (0.9.42)

With Fantastico De Luxe you can
- install in the main directory, in addon domains and in subdomains
- create Features Sets so different users have different set of available scripts
- translate the English language file and give your clients auto-installation in their own language
- get notifications when users install/remove applications
- have a complete overview over the installations performed by your users