GNOME or Nautilus filetype associations

[Paul Galbraith <paul@paulgalbraith.net>]

I'm running Sarge, and in Nautilus all XML documents are somehow 
associated with the project manager application.  I've set the mime type 
association to default to use gvim to edit .xml files, but Nautilus 
seems to ignore this.  Does anyone know how to change the association 
that Nautilus uses?