Possible, yes, but advisable? I don't think so. For starters you can do all kinds of things in Word that you cannot do on an IP phone display. For display you either have to settle for simple text (CiscoIPPhoneText) or do something graphical (which means drawing text into an image.. ). So even though you can theoretically do nifty formatting, you'd need to write an application that turns bits of the Word document into an image.
So my advice is to use a simple web interface, analogue to the Push2phone sample from the SDK, where people can compose Text messages and that's that. Or put the text atop a company log, as you please. But word to IP Phone, that opens so many cans of worms you'll end up wishing you hadn't proposed that idea. (another worm that comes to mind is that you need to have a well defined "news separator", and if people forget to add that you cannot separate news items and end up distributing multiple ones, so the new one and old ones", and what will you do if an old one is updated, etc).
As for the distribution, take a look at the push2phone sample.. it's basically how you get things out to an IP phone without having to resort to a service.
As I said I'd use the webpage approach. Give access to that webpage to your marketing department, and make it possible to send news to only groups of people as well as everyone, so that people pushing the news will be able to test formatting, etc, before they send something ill conceived to everyone.
