Started with the alternatives for GoogleDocs and after reading here the post about alternatives for proprietary software, I've decided to continue with the alternatives for another famous proprietary software, but for project management. The application is called Basecamp. As you may know, there are a lot of good open source alternatives for Basecamp, which would help you to manage your projects totally for free. Let's review some of these applications...
phpCollab is an open source internet-enabled system for use in projects that require collaboration over the internet. The most wanted features are included: features team/client sites, task assignment, document repository/workflow, gantt charts, discussions, calendar, notifications, support requests, weblog newsdesk, invoicing, etc..
TeamLab business collaboration platform is an open-source software. TeamLab source code is listed on SourceForge and distributed under GNU GPL v3 license terms. It is available for download and deployment on your own server.
dotProject is a volunteer supported Project Management application. There is no "company" behind this project, it is managed, maintained, developed and supported by a volunteer group and by the users themselves.