Go to the file associations in kcontrol and check the embedded options for koffice-files.
Use that information to change the settings voor MS Office-files.
In the past there was a plugin available that could use openoffice to watch documents inline in Konqueror.
Dunno if that is still available.
For information about kparts, you can checkout developer.kde.org.
this is a tutorial from that site about kparts:
http://developer.kde.org/documentation/tutorials/kparts/