Free PM Tools

ToolCategoryDescription
Redmine Issues and Bug tracking system
 A general issue and bug tracking tool. Open source and free. You will need to install it on your own webserver and it works with Ruby on Rails, so this is a diversion from the usual PHP based open source software. I found it very powerful and customisable. Ability to manage many projects, track time spent on bugs or features and has some additional components such as Wiki and document management.
 Collabtive Tasks management, Timesheet, Collaboration
 An open source PHP/Mysql collaboration system. Read my review.
 OpenAtrium Intranet, Collaboration
An open source Intranet and Collaboration tool. Read my review.
 Xmind Mind Mapping
 A mind mapping free software that allows you to arrange the map in hierarchical structure so nice to draw WBS. There is a paid version as well with online capabilities.
ComappingMind MappingA mind mapping ONLINE software. Does not bring the WBS and numbering capabilities that x-mind brings but it is an online system that allows you to share your mindmaps with others, I use it for this reason. There is a free and a chargeable version. The free one being relatively functional but after a month you can only view your mind maps and not edit them. So you will quickly have to switch to a paid version.
OpenProjGantt ChartAn alternative to MS Project. It has been acquired by Serena who pledged to keep it free alongside a paid SaaS model.
GanttProjectGantt ChartA Java based alternative to MS Project
GantterGantt ChartNeed to open a MS project file but don't have MS? Use Gantter.com, extremely simple to use. It's an online Gantt chart application. You can share documents but you can save them on your computer, import from MS project.