ProjectLibre is the Open-Source alternative to Microsoft Project.
ProjectLibre is compatible with Microsoft Project 2003, 2007 and 2010 files,
you can simply open them on Linux, Mac OS or Windows and if desired save the
results back. The ProjectLibre team has been the key innovators in project
management software dating to the mainframe/Dos/Windows markets and released
the very first web-based project solution..... (in Business and Productivity)