Change application for MIME types in gnome 2.8

[Henrik Ormåsen <henrik ormasen sos-rasisme no>]

I have at terminalserver, debian testing, and should like to change
the mime registration, so that nautilus, thunderbird, etc. starts
openoffice. word documents, etc. in openoffice 1.1.2. 

The problem is that after I installed openoffice2 Beta, this has
become the default for those files.

How do I change this for all users?

I have searched for documentation, but not found anything. The 2.6
admin guide is outdated for this case.

Regards Henrik