I am sure you have been in a situation where you need to open a MS Project file but do not have MS Project. Now, you have easy solulion. It is called "OpenProj", an open source, freeware software by Projity is a desktop replacement of Microsoft Project. OpenProj has equivalent functionality, a familiar user interface and even opens existing MSProject files. OpenProj is interoperable with Project, with a Gantt Chart and PERT chart etc. Check it out at: http://sourceforge.net/projects/openproj/