Tasks is built on PHP and MySQL. It features a dynamic hierarchical view of your tasks, scheduling due dates, and associating URLs with and uploading and attaching files to tasks. RSS Feeds and iCalendars of your tasks are available. There is a mobile interface for use with a Web-enabled PDA or cell phone.
PHP Doc System allows developers to create modules for documentation elements (installation steps, buttons, screens, etc.) and then refer to them instead of having to copy/paste information they'd want to have in two or more places. It can run as dynamic PHP, including everything on the fly or it can output static HTML that can be included in a software distribution.
photos is a Web-based photo database for storing metadata about digital photos so you can find them again later. It supports adding photos one at a time, or as a group by directory. It is intended to be run locally but can be run on a remote Web server if you've got the space and the bandwidth.
Tasks Pro is a Web-based hierarchical task manager with polished multi-user functionality. Features include advanced user and task permissions, email notifications and reminders, RSS feeds and iCalendars for all users and groups, full localization support, and a rich, powerful interface that is a pleasure to use.
RE: Sharing Outlook Calendars
Tasks creates iCalendars, which can be subscribed to in iCalendar programs or viewed online. Several customers have posted Outlook "psuedo-integrations" in the forums (show Tasks when clicking on the Outlook tasks button for example) and there is an Outlook plugin that allows you to subscribe to iCalendars (though I haven't tested it).