How to open a mpp file? Whish s/w is suitable?

I think you need Microsoft project.

There are many free software to open a mpp file.

There are 5 solutions listed here on how to open a .mpp file without MS Project installed (http://www.wareprise.com/2009/08/20/how-to-open-and-view-mpp-file-without-ms-project-installed/).

Yeah, there's lots of software available. Some offer comparability with Mac, Linux and obviously Windows.

I personally use these guys, they have a free demo available if you want to try:
Microsoft Project | Viewer | Steelray (http://www.steelray.com/steelray_project_viewer_overview.php)

Make use of following solution to open mpp files corrupt powerpoint fix software (http://www.powerpoint.fixtoolboxx.com/)