Changing default app for application/pdf in Gnome?

[Steve Bergman <steve@xxxxxxxx>]

I would like to change the default app for aplication/pdf files from ggv 
to xpdf on a system wide basis.

How can I do this?

Also, it Mozilla's behavior that I an really wanting to change system 
wide, but as there are no specific definitions for application/pdf in 
mozilla, I assume it is using Gnome's mime defaults.

Thanks,
Steve Bergman