Planner is a project management tool (formerly called Mr Project). Its principal incarnation is for the Gnome desktop. But it also has a Windows version (see references). Planner is released under the GNU GPL licence. If you want to try it, there is a copy on the live Linux CD, the OSS Watch Knoppix.
If you have never used project management software previously, you may find Planner is just what you are looking for. Even if you are a regular user of proprietary project management software, you may find that Planner has most of the features that you actually need and use, without the added bulk (or cost).
Are you using Planner? Edit this page to tell us about your experiences.
As of this writing, Planner v 0.13, I found Planner fully usable. Some features, such as the export to html, are especially attractive. That turns a standalone project planning program into a resource with shareable outputs.
I put Planner through its paces by using it on a practical, but short term, project. The biggest hurdle is getting your head around project planning itself. If you don't already know about work breakdown structures then you should probably read up on project planning first. This is not a problem with the software, by the way. Work breakdown structure, dividing the project into manageable assigned tasks divided into the four phases of project management - initiation, planning, execution and closure - is really something that needs to be done on scraps of paper. Once I had learned a bit more about that, I found Planner thoroughly intuitive. The moral is that project planning software is no substitute for a bit of skill development on project planning itself.
As I find myself moving almost daily between a Linux desktop and a Windows desktop, I especially liked the fact that I could edit the same .planner file in either operating system. The user experience was roughly equivalent in both which makes Planner a versatile project planning tool. RandyMetcalfe