Powerpoint 2007 compatability

I am working on a project for class that is being created in Powerpoint 2007, file extension .ppsx, that cannot be opened with Microsoft Office 2004 on the Mac. Is there a converter or application that allows people to view a presentation on a Mac created in Powerpoint 2007?

There will be people with various versions of OS and Microsoft Office having access to this presentation.

Thank you.