The number of great software projects that I never knew existed is simply amazing.
Today I started using Serena OpenProj. This is an open source (http://sourceforge.net/projects/openproj) application that is freely available to run and use. The amazing thing is that it works just like Microsoft Project!!!! Yep. First thing I tried was to open an MS-Project file I had been working on a few minutes earlier and just basically continued editing it with OpenProj. The user interface is somewhat different and not quite as crisp, but that is mainly because this is a Java program that I can run on any platform, not just Windows.
It is not all super sweet, there are some very minor drawbacks. If you print out your project plan and are used to the specific look of MS Project Gantt charts, well...it is going to be a little different. Oh...and don't expect to save it back as an .mpp file format. You can save it as xml and then open the xml from MS Project. Also if you are a true power user of MSProject, then there are numerous other minor things you will immediately notice. But if all you need is a way to build the gantt, set up dependencies, use it to manage your project with...THIS IS IT...and it is open source! Free :)