Did they announce this previously or are they giving just a 5 day notice(only 3 working days given the weekend)? A lot of users are going to get irritated at having to change their workflow to have a copy of Office to re-save documents before uploading them. If you need to have a copy of Office around to save them in the new format, then some of the savings by using Google Apps is diminished.
That's the thought that goes through my mind when I hear the "Yay, cloud!" line from the following MS ad: