Sometimes its hard to organise peoples work in one big or worldwide project.
Groupwork/CRM web based systems are very helpfully in that situations.

Ofc There is many of paid solutions in web but it is also some opensource projects:

- ACollab
- Achievo
- Collabtive
- dotProject
- eGroupWare
- Flyspray
- GroupOffice
- OpenGoo
- SugarCRM
- WebCollab
- PHProjekt

personally I recoccmend SugarCRM