Primavera Project Planner for Windows is a PM tool for professional project managers. It was designed by PM experts to be used by other experts. It's not something to be taken lightly. Plan on spending at least a half a year becoming familiar with all the parts of this tool and the rest of your career putting the concepts of PM into practice.
P3 is the equivalent of a sophisticated time and resource spreadsheet. Just as you can play "what if" games with a spreadsheet, so too can you play "what if" we reassign Joe to work on this part of the project? What if we throw more money into the middle part of the project? Will it help us speed things up?
It also lets you organize your projects by responsibility, resources, weekly calendar dates, phases of the project, etc. and you can color each view differently for ease of recognition.
P3 also gives you WYSIWYG graphics and more than 75 standard reports. You can preview the reports on-screen and modify them to suit the format of the final report.
To see more of what Primavera can do take a look at A Software Development Project